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Lactate dehydrogenase

Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of pyruvate to lactate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from one molecule to another.

Lactate dehydrogenase
Lactate dehydrogenase M tetramer (LDH5), Human
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EC no.1.1.1.27
CAS no.9001-60-9
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LDH exists in four distinct enzyme classes. This article is specifically about the NAD(P)-dependent L-lactate dehydrogenase. Other LDHs act on D-lactate and/or are dependent on cytochrome c: D-lactate dehydrogenase (cytochrome) and L-lactate dehydrogenase (cytochrome).

LDH is expressed extensively in body tissues, such as blood cells and heart muscle. Because it is released during tissue damage, it is a marker of common injuries and disease such as heart failure.

Reaction edit

 
Reaction catalyzed by lactate dehydrogenase

Lactate dehydrogenase catalyzes the interconversion of pyruvate and lactate with concomitant interconversion of NADH and NAD+. It converts pyruvate, the final product of glycolysis, to lactate when oxygen is absent or in short supply, and it performs the reverse reaction during the Cori cycle in the liver. At high concentrations of lactate, the enzyme exhibits feedback inhibition, and the rate of conversion of pyruvate to lactate is decreased. It also catalyzes the dehydrogenation of 2-hydroxybutyrate, but this is a much poorer substrate than lactate.

Active site edit

 
Arrow pushing mechanism for the reaction catalyzed by lactate dehydrogenase

LDH in humans uses His(193) as the proton acceptor, and works in unison with the coenzyme (Arg99 and Asn138), and substrate (Arg106; Arg169; Thr248) binding residues.[1][2] The His(193) active site, is not only found in the human form of LDH, but is found in many different animals, showing the convergent evolution of LDH. The two different subunits of LDH (LDHA, also known as the M subunit of LDH, and LDHB, also known as the H subunit of LDH) both retain the same active site and the same amino acids participating in the reaction. The noticeable difference between the two subunits that make up LDH's tertiary structure is the replacement of alanine (in the M chain) with a glutamine (in the H chain). This tiny but notable change is believed to be the reason the H subunit can bind NAD faster, and the M subunit's catalytic activity isn't reduced in the presence of acetylpyridine adenine dinucleotide, whereas the H subunit's activity is reduced fivefold.[3]

Isoenzymes edit

Enzymatically active lactate dehydrogenase is consisting of four subunits (tetramer). The two most common subunits are the LDH-M and LDH-H peptides, named for their discovery in muscle and heart tissue, and encoded by the LDHA and LDHB genes, respectively. These two subunits can form five possible tetramers (isoenzymes): LDH-1 (4H), LDH-5 (4M), and the three mixed tetramers (LDH-2/3H1M, LDH-3/2H2M, LDH-4/1H3M). These five isoforms are enzymatically similar but show different tissue distribution.

LDH-2 is usually the predominant form in the serum. An LDH-1 level higher than the LDH-2 level (a "flipped pattern") suggests myocardial infarction (damage to heart tissues releases heart LDH, which is rich in LDH-1, into the bloodstream). The use of this phenomenon to diagnose infarction has been largely superseded by the use of Troponin I or T measurement.[citation needed]

There are two more mammalian LDH subunits that can be included in LDH tetramers: LDHC and LDHBx. LDHC is a testes-specific LDH protein, that is encoded by the LDHC gene. LDHBx is a peroxisome-specific LDH protein. LDHBx is the readthrough-form of LDHB. LDHBx is generated by translation of the LDHB mRNA, but the stop codon is interpreted as an amino acid-encoding codon. In consequence, translation continues to the next stop codon. This leads to the addition of seven amino acid residues to the normal LDH-H protein. The extension contains a peroxisomal targeting signal, so that LDHBx is imported into the peroxisome.[6]

Protein families edit

The family also contains L-lactate dehydrogenases that catalyse the conversion of pyruvate to L-lactate, the last step in anaerobic glycolysis. Malate dehydrogenases that catalyse the interconversion of malate to oxaloacetate and participate in the citric acid cycle, and L-2-hydroxyisocaproate dehydrogenases are also members of the family. The N-terminus is a Rossmann NAD-binding fold and the C-terminus is an unusual alpha+beta fold.[7][8]

Interactive pathway map edit

Click on genes, proteins and metabolites below to link to respective articles.[§ 1]

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|alt=Glycolysis and Gluconeogenesis edit]]
Glycolysis and Gluconeogenesis edit
  1. ^ The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534".

Enzyme regulation edit

This protein may use the morpheein model of allosteric regulation.[9]

Ethanol-induced hypoglycemia edit

Ethanol is dehydrogenated to acetaldehyde by alcohol dehydrogenase, and further into acetyl CoA by acetaldehyde dehydrogenase. During this reaction 2 NADH are produced. If large amounts of ethanol are present, then large amounts of NADH are produced, leading to a depletion of NAD+. Thus, the conversion of pyruvate to lactate is increased due to the associated regeneration of NAD+. Therefore, anion-gap metabolic acidosis (lactic acidosis) may ensue in ethanol poisoning.

The increased NADH/NAD+ ratio also can cause hypoglycemia in an (otherwise) fasting individual who has been drinking and is dependent on gluconeogenesis to maintain blood glucose levels. Alanine and lactate are major gluconeogenic precursors that enter gluconeogenesis as pyruvate. The high NADH/NAD+ ratio shifts the lactate dehydrogenase equilibrium to lactate, so that less pyruvate can be formed and, therefore, gluconeogenesis is impaired.

Substrate regulation edit

LDH is also regulated by the relative concentrations of its substrates. LDH becomes more active under periods of extreme muscular output due to an increase in substrates for the LDH reaction. When skeletal muscles are pushed to produce high levels of power, the demand for ATP in regards to aerobic ATP supply leads to an accumulation of free ADP, AMP, and Pi. The subsequent glycolytic flux, specifically production of pyruvate, exceeds the capacity for pyruvate dehydrogenase and other shuttle enzymes to metabolize pyruvate. The flux through LDH increases in response to increased levels of pyruvate and NADH to metabolize pyruvate into lactate.[10]

Transcriptional regulation edit

LDH undergoes transcriptional regulation by PGC-1α. PGC-1α regulates LDH by decreasing LDH A mRNA transcription and the enzymatic activity of pyruvate to lactate conversion.[11]

Genetics edit

The M and H subunits are encoded by two different genes:

  • The M subunit is encoded by LDHA, located on chromosome 11p15.4 (Online Mendelian Inheritance in Man (OMIM): 150000).
  • The H subunit is encoded by LDHB, located on chromosome 12p12.2-p12.1 (Online Mendelian Inheritance in Man (OMIM): 150100).
  • A third isoform, LDHC or LDHX, is expressed only in the testis (Online Mendelian Inheritance in Man (OMIM): 150150); its gene is likely a duplicate of LDHA and is also located on the eleventh chromosome (11p15.5-p15.3).
  • The fourth isoform is localized in the peroxisome. It is tetramer containing one LDHBx subunit, which is also encoded by the LDHB gene. The LDHBx protein is seven amino acids longer than the LDHB (LDH-H) protein. This amino acid extension is generated by functional translational readthrough.[6]

Mutations of the M subunit have been linked to the rare disease exertional myoglobinuria (see OMIM article), and mutations of the H subunit have been described but do not appear to lead to disease.

Mutations edit

 
This is a mutant version of the LDH-5 enzyme, which is usually found in skeletal muscle

In rare cases, a mutation in the genes controlling the production of lactate dehydrogenase will lead to a medical condition known as lactate dehydrogenase deficiency. Depending on which gene carries the mutation, one of two types will occur: either lactate dehydrogenase-A deficiency (also known as glycogen storage disease XI) or lactate dehydrogenase-B deficiency. Both of these conditions affect how the body breaks down sugars, primarily in certain muscle cells. Lactate dehydrogenase-A deficiency is caused by a mutation to the LDHA gene, while lactate dehydrogenase-B deficiency is caused by a mutation to the LDHB gene.[12]

This condition is inherited in an autosomal recessive pattern, meaning that both parents must contribute a mutated gene in order for this condition to be expressed.[13]

A complete lactate dehydrogenase enzyme consists of four protein subunits.[14] Since the two most common subunits found in lactate dehydrogenase are encoded by the LDHA and LDHB genes, either variation of this disease causes abnormalities in many of the lactate dehydrogenase enzymes found in the body. In the case of lactate dehydrogenase-A deficiency, mutations to the LDHA gene result in the production of an abnormal lactate dehydrogenase-A subunit that cannot bind to the other subunits to form the complete enzyme. This lack of a functional subunit reduces the amount of enzyme formed, leading to an overall decrease in activity. During the anaerobic phase of glycolysis (the Cori cycle), the mutated enzyme is unable to convert pyruvate into lactate to produce the extra energy the cells need. Since this subunit has the highest concentration in the LDH enzymes found in the skeletal muscles (which are the primary muscles responsible for movement), high-intensity physical activity will lead to an insufficient amount of energy being produced during this anaerobic phase.[15] This in turn will cause the muscle tissue to weaken and eventually break down, a condition known as rhabdomyolysis. The process of rhabdomyolysis also releases myoglobin into the blood, which will eventually end up in the urine and cause it to become red or brown: another condition known as myoglobinuria.[16] Some other common symptoms are exercise intolerance, which consists of fatigue, muscle pain, and cramps during exercise, and skin rashes.[17][18] In severe cases, myoglobinuria can damage the kidneys and lead to life-threatening kidney failure.[19] In order to obtain a definitive diagnosis, a muscle biopsy may be performed to confirm low or absent LDH activity. There is currently no specific treatment for this condition.

In the case of lactate dehydrogenase-B deficiency, mutations to the LDHB gene result in the production of an abnormal lactate dehydrogenase-B subunit that cannot bind to the other subunits to form the complete enzyme. As with lactate dehydrogenase-A deficiency, this mutation reduces the overall effectiveness in the enzyme.[20] However, there are some major differences between these two cases. The first is the location where the condition manifests itself. With lactate dehydrogenase-B deficiency, the highest concentration of B subunits can be found within the cardiac muscle, or the heart. Within the heart, lactate dehydrogenase plays the role of converting lactate back into pyruvate so that the pyruvate can be used again to create more energy.[21] With the mutated enzyme, the overall rate of this conversion is decreased. However, unlike lactate dehydrogenase-A deficiency, this mutation does not appear to cause any symptoms or health problems linked to this condition.[18][22] At the present moment, it is unclear why this is the case. Affected individuals are usually discovered only when routine blood tests indicate low LDH levels present within the blood.

Role in muscular fatigue edit

The onset of acidosis during periods of intense exercise is commonly attributed to accumulation of hydrogens that are dissociated from lactate. Previously, lactic acid was thought to cause fatigue. From this reasoning, the idea of lactate production being a primary cause of muscle fatigue during exercise was widely adopted. A closer, mechanistic analysis of lactate production under “anaerobic” conditions shows that there is no biochemical evidence for the production of lactate through LDH contributing to acidosis. While LDH activity is correlated to muscle fatigue,[23] the production of lactate by means of the LDH complex works as a system to delay the onset of muscle fatigue. George Brooks and Colleagues at UC Berkeley where the lactate shuttle was discovered showed that lactate was actually a metabolic fuel not a waste product or the cause of fatigue.

LDH works to prevent muscular failure and fatigue in multiple ways. The lactate-forming reaction generates cytosolic NAD+, which feeds into the glyceraldehyde 3-phosphate dehydrogenase reaction to help maintain cytosolic redox potential and promote substrate flux through the second phase of glycolysis to promote ATP generation. This, in effect, provides more energy to contracting muscles under heavy workloads. The production and removal of lactate from the cell also ejects a proton consumed in the LDH reaction- the removal of excess protons produced in the wake of this fermentation reaction serves to act as a buffer system for muscle acidosis.[citation needed] Once proton accumulation exceeds the rate of uptake in lactate production and removal through the LDH symport,[24] muscular acidosis occurs.

Blood test edit

Reference ranges for blood tests for lactate dehydrogenase
Lower limit Upper limit Unit Comments
50[25] 150[25] U/L
0.4[26] 1.7[26] μmol/L
1.8[27] 3.4[27] µkat/L < 70 years old[27]

On blood tests, an elevated level of lactate dehydrogenase usually indicates tissue damage, which has multiple potential causes, reflecting its widespread tissue distribution:

Low and normal levels of LDH do not usually indicate any pathology.[28] Low levels may be caused by large intake of vitamin C.

LDH is a protein that normally appears throughout the body in small amounts.

Testing in cancer edit

 
Comparison of LDH activity in normal and cancerous cells

Many cancers can raise LDH levels, so LDH may be used as a tumor marker, but at the same time, it is not useful in identifying a specific kind of cancer. Measuring LDH levels can be helpful in monitoring treatment for cancer. Noncancerous conditions that can raise LDH levels include heart failure, hypothyroidism, anemia, pre-eclampsia, meningitis, encephalitis, acute pancreatitis, HIV and lung or liver disease.[30]

Tissue breakdown releases LDH, and therefore, LDH can be measured as a surrogate for tissue breakdown (e.g., hemolysis). LDH is measured by the lactate dehydrogenase (LDH) test (also known as the LDH test or lactic acid dehydrogenase test). Comparison of the measured LDH values with the normal range help guide diagnosis.[31]

Hemolysis edit

In medicine, LDH is often used as a marker of tissue breakdown as LDH is abundant in red blood cells and can function as a marker for hemolysis. A blood sample that has been handled incorrectly can show false-positively high levels of LDH due to erythrocyte damage.

It can also be used as a marker of myocardial infarction. Following a myocardial infarction, levels of LDH peak at 3–4 days and remain elevated for up to 10 days. In this way, elevated levels of LDH (where the level of LDH1 is higher than that of LDH2, i.e. the LDH Flip, as normally, in serum, LDH2 is higher than LDH1) can be useful for determining whether a patient has had a myocardial infarction if they come to doctors several days after an episode of chest pain.

Tissue turnover edit

Other uses are assessment of tissue breakdown in general; this is possible when there are no other indicators of hemolysis. It is used to follow up cancer (especially lymphoma) patients, as cancer cells have a high rate of turnover, with destroyed cells leading to an elevated LDH activity.

HIV edit

LDH is often measured in HIV patients as a non-specific marker for pneumonia due to Pneumocystis jirovecii (PCP). Elevated LDH in the setting of upper respiratory symptoms in a HIV patient suggests, but is not diagnostic for, PCP. However, in HIV-positive patients with respiratory symptoms, a very high LDH level (>600 IU/L) indicated histoplasmosis (9.33 times more likely) in a study of 120 PCP and 30 histoplasmosis patients.[32]

Testing in other body fluids edit

Exudates and transudates edit

Measuring LDH in fluid aspirated from a pleural effusion (or pericardial effusion) can help in the distinction between exudates (actively secreted fluid, e.g., due to inflammation) or transudates (passively secreted fluid, due to a high hydrostatic pressure or a low oncotic pressure). The usual criterion (included in Light's criteria) is that a ratio of pleural LDH to serum LDH greater than 0.6[33] or 23 the upper limit of the normal laboratory value for serum LDH[34] indicates an exudate, while a ratio of less indicates a transudate. Different laboratories have different values for the upper limit of serum LDH, but examples include 200[35] and 300[35] IU/L.[36] In empyema, the LDH levels, in general, will exceed 1000 IU/L.

Meningitis and encephalitis edit

High levels of lactate dehydrogenase in cerebrospinal fluid are often associated with bacterial meningitis.[37] In the case of viral meningitis, high LDH, in general, indicates the presence of encephalitis and poor prognosis.

In cancer treatment edit

LDH is involved in tumor initiation and metabolism. Cancer cells rely on increased glycolysis resulting in increased lactate production in addition to aerobic respiration in the mitochondria, even under oxygen-sufficient conditions (a process known as the Warburg effect[38]). This state of fermentative glycolysis is catalyzed by the A form of LDH. This mechanism allows tumorous cells to convert the majority of their glucose stores into lactate regardless of oxygen availability, shifting use of glucose metabolites from simple energy production to the promotion of accelerated cell growth and replication.

LDH A and the possibility of inhibiting its activity has been identified as a promising target in cancer treatments focused on preventing carcinogenic cells from proliferating. Chemical inhibition of LDH A has demonstrated marked changes in metabolic processes and overall survival of carcinoma cells. Oxamate is a cytosolic inhibitor of LDH A that significantly decreases ATP production in tumorous cells as well as increasing production of reactive oxygen species (ROS). These ROS drive cancer cell proliferation by activating kinases that drive cell cycle progression growth factors at low concentrations,[39] but can damage DNA through oxidative stress at higher concentrations. Secondary lipid oxidation products can also inactivate LDH and impact its ability to regenerate NADH,[40] directly disrupting the enzymes ability to convert lactate to pyruvate.

While recent studies have shown that LDH activity is not necessarily an indicator of metastatic risk,[41] LDH expression can act as a general marker in the prognosis of cancers. Expression of LDH5 and VEGF in tumors and the stroma has been found to be a strong prognostic factor for diffuse or mixed-type gastric cancers.[42]

Prokaryotes edit

A cap-membrane-binding domain is found in prokaryotic lactate dehydrogenase. This consists of a large seven-stranded antiparallel beta-sheet flanked on both sides by alpha-helices. It allows for membrane association.[43]

See also edit

References edit

This article incorporates text from the public domain Pfam and InterPro: IPR015409
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  2. ^ Wilks HM, Holbrook JJ (December 1988). "A Specific, Highly Active Malate Dehydrogenase by Redesign of a Lactate Dehydrogenase Framework". Science. 242 (4885): 1541–44. Bibcode:1988Sci...242.1541W. doi:10.1126/science.3201242. PMID 3201242.
  3. ^ Eventoff W, Rossmann MG, Taylor SS, Torff HJ, Meyer H, Keil W, Kiltz HH (July 1977). "Structural adaptations of lactate dehydrogenase isozymes". Proceedings of the National Academy of Sciences of the United States of America. 74 (7): 2677–81. Bibcode:1977PNAS...74.2677E. doi:10.1073/pnas.74.7.2677. PMC 431242. PMID 197516.
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Further reading edit

  • Johnson WT, Canfield WK (1985). "Intestinal absorption and excretion of zinc in streptozotocin-diabetic rats as affected by dietary zinc and protein". J Nutr. 115 (9): 1217–27. doi:10.1093/jn/115.9.1217. PMID 3897486.
  • Ein SH, Mancer K, Adeyemi SD (1985). "Malignant sacrococcygeal teratoma--endodermal sinus, yolk sac tumor--in infants and children: a 32-year review". J Pediatr Surg. 20 (5): 473–7. doi:10.1016/s0022-3468(85)80468-1. PMID 3903096.
  • Azuma M, Shi M, Danenberg KD, Gardner H, Barrett C, Jacques CJ, Sherod A, Iqbal S, El-Khoueiry A, Yang D, Zhang W, Danenberg PV, Lenz HJ (2007). "Serum lactate dehydrogenase levels and glycolysis significantly correlate with tumor VEGFA and VEGFR expression in metastatic CRC patients". Pharmacogenomics. 8 (12): 1705–13. doi:10.2217/14622416.8.12.1705. PMID 18086000.
  • Masepohl B, Klipp W, Pühler A (1988). "Genetic characterization and sequence analysis of the duplicated nifA/nifB gene region of Rhodobacter capsulatus". Mol Gen Genet. 212 (1): 27–37. doi:10.1007/bf00322441. PMID 2836706. S2CID 21009965.
  • Galardo MN, Regueira M, Riera MF, Pellizzari EH, Cigorraga SB, Meroni SB (2014). "Lactate Regulates Rat Male Germ Cell Function through Reactive Oxygen Species". PLOS ONE. 9 (1): e88024. Bibcode:2014PLoSO...988024G. doi:10.1371/journal.pone.0088024. PMC 3909278. PMID 24498241.
  • Tesch P, Sjödin B, Thorstensson A, Karlsson J (1978). "Muscle fatigue and its relation to lactate accumulation and LDH activity in man". Acta Physiol Scand. 103 (4): 413–20. doi:10.1111/j.1748-1716.1978.tb06235.x. PMID 716962.
  • Beck O, Jernström B, Martinez M, Repke DB (1988). "In vitro study of the aromatic hydroxylation of 1-methyltetrahydro-beta-carboline (methtryptoline) in rat". Chem Biol Interact. 65 (1): 97–106. doi:10.1016/0009-2797(88)90034-8. PMID 3345575.
  • Summermatter S, Santos G, Pérez-Schindler J, Handschin C (2013). "Skeletal muscle PGC-1α controls whole-body lactate homeostasis through estrogen-related receptor α-dependent activation of LDH B and repression of LDH A." Proc Natl Acad Sci U S A. 110 (21): 8738–43. Bibcode:2013PNAS..110.8738S. doi:10.1073/pnas.1212976110. PMC 3666691. PMID 23650363.
  • Robergs RA, Ghiasvand F, Parker D (2004). "Biochemistry of exercise-induced metabolic acidosis". Am J Physiol Regul Integr Comp Physiol. 287 (3): R502-16. doi:10.1152/ajpregu.00114.2004. PMID 15308499. S2CID 2745168.
  • Kresge N, Simoni RD, Hill RL (2005). "Otto Fritz Meyerhof and the elucidation of the glycolytic pathway". J Biol Chem. 280 (4): e3. doi:10.1016/S0021-9258(20)76366-0. PMID 15665335.

External links edit

  •   Media related to Lactate dehydrogenase at Wikimedia Commons

lactate, dehydrogenase, enzyme, found, nearly, living, cells, catalyzes, conversion, pyruvate, lactate, back, converts, nadh, back, dehydrogenase, enzyme, that, transfers, hydride, from, molecule, another, tetramer, ldh5, humanidentifiersec, 27cas, 9001, 9data. Lactate dehydrogenase LDH or LD is an enzyme found in nearly all living cells LDH catalyzes the conversion of pyruvate to lactate and back as it converts NAD to NADH and back A dehydrogenase is an enzyme that transfers a hydride from one molecule to another Lactate dehydrogenaseLactate dehydrogenase M tetramer LDH5 HumanIdentifiersEC no 1 1 1 27CAS no 9001 60 9DatabasesIntEnzIntEnz viewBRENDABRENDA entryExPASyNiceZyme viewKEGGKEGG entryMetaCycmetabolic pathwayPRIAMprofilePDB structuresRCSB PDB PDBe PDBsumGene OntologyAmiGO QuickGOSearchPMCarticlesPubMedarticlesNCBIproteinsLDH exists in four distinct enzyme classes This article is specifically about the NAD P dependent L lactate dehydrogenase Other LDHs act on D lactate and or are dependent on cytochrome c D lactate dehydrogenase cytochrome and L lactate dehydrogenase cytochrome LDH is expressed extensively in body tissues such as blood cells and heart muscle Because it is released during tissue damage it is a marker of common injuries and disease such as heart failure Contents 1 Reaction 2 Active site 3 Isoenzymes 4 Protein families 5 Interactive pathway map 6 Enzyme regulation 6 1 Ethanol induced hypoglycemia 6 2 Substrate regulation 6 3 Transcriptional regulation 7 Genetics 7 1 Mutations 8 Role in muscular fatigue 9 Blood test 9 1 Testing in cancer 9 2 Hemolysis 9 3 Tissue turnover 9 4 HIV 10 Testing in other body fluids 10 1 Exudates and transudates 10 2 Meningitis and encephalitis 11 In cancer treatment 12 Prokaryotes 13 See also 14 References 15 Further reading 16 External linksReaction edit nbsp Reaction catalyzed by lactate dehydrogenaseLactate dehydrogenase catalyzes the interconversion of pyruvate and lactate with concomitant interconversion of NADH and NAD It converts pyruvate the final product of glycolysis to lactate when oxygen is absent or in short supply and it performs the reverse reaction during the Cori cycle in the liver At high concentrations of lactate the enzyme exhibits feedback inhibition and the rate of conversion of pyruvate to lactate is decreased It also catalyzes the dehydrogenation of 2 hydroxybutyrate but this is a much poorer substrate than lactate Active site edit nbsp Arrow pushing mechanism for the reaction catalyzed by lactate dehydrogenaseLDH in humans uses His 193 as the proton acceptor and works in unison with the coenzyme Arg99 and Asn138 and substrate Arg106 Arg169 Thr248 binding residues 1 2 The His 193 active site is not only found in the human form of LDH but is found in many different animals showing the convergent evolution of LDH The two different subunits of LDH LDHA also known as the M subunit of LDH and LDHB also known as the H subunit of LDH both retain the same active site and the same amino acids participating in the reaction The noticeable difference between the two subunits that make up LDH s tertiary structure is the replacement of alanine in the M chain with a glutamine in the H chain This tiny but notable change is believed to be the reason the H subunit can bind NAD faster and the M subunit s catalytic activity isn t reduced in the presence of acetylpyridine adenine dinucleotide whereas the H subunit s activity is reduced fivefold 3 Isoenzymes editEnzymatically active lactate dehydrogenase is consisting of four subunits tetramer The two most common subunits are the LDH M and LDH H peptides named for their discovery in muscle and heart tissue and encoded by the LDHA and LDHB genes respectively These two subunits can form five possible tetramers isoenzymes LDH 1 4H LDH 5 4M and the three mixed tetramers LDH 2 3H1M LDH 3 2H2M LDH 4 1H3M These five isoforms are enzymatically similar but show different tissue distribution LDH 1 4H in the heart and in RBC red blood cells as well as the brain 4 LDH 2 3H1M in the reticuloendothelial system LDH 3 2H2M in the lungs LDH 4 1H3M in the kidneys placenta and pancreas LDH 5 4M in the liver and striated muscle 5 also present in the brain 4 LDH 2 is usually the predominant form in the serum An LDH 1 level higher than the LDH 2 level a flipped pattern suggests myocardial infarction damage to heart tissues releases heart LDH which is rich in LDH 1 into the bloodstream The use of this phenomenon to diagnose infarction has been largely superseded by the use of Troponin I or T measurement citation needed There are two more mammalian LDH subunits that can be included in LDH tetramers LDHC and LDHBx LDHC is a testes specific LDH protein that is encoded by the LDHC gene LDHBx is a peroxisome specific LDH protein LDHBx is the readthrough form of LDHB LDHBx is generated by translation of the LDHB mRNA but the stop codon is interpreted as an amino acid encoding codon In consequence translation continues to the next stop codon This leads to the addition of seven amino acid residues to the normal LDH H protein The extension contains a peroxisomal targeting signal so that LDHBx is imported into the peroxisome 6 lactate dehydrogenase A subunit M nbsp Human lactate dehydrogenase M4 the isoenzyme found in skeletal muscle From PDB 1I10 IdentifiersSymbolLDHAAlt symbolsLDHMNCBI gene3939HGNC6535OMIM150000RefSeqNM 005566UniProtP00338Other dataEC number1 1 1 27LocusChr 11 p15 4Search forStructuresSwiss modelDomainsInterPro lactate dehydrogenase B subunit H nbsp Crystal structure of B lactate dehydrogenase From PDB 1T2F IdentifiersSymbolLDHBAlt symbolsLDHLNCBI gene3945HGNC6541OMIM150100RefSeqNM 002300UniProtP07195Other dataEC number1 1 1 27LocusChr 12 p12 2 12 1Search forStructuresSwiss modelDomainsInterPro lactate dehydrogenase C nbsp Crystal structure of Mouse Testicular Lactate dehydrogenase C4 From PDB 2LDX IdentifiersSymbolLDHCNCBI gene3948HGNC6544OMIM150150RefSeqNM 002301UniProtP07864Other dataEC number1 1 1 27LocusChr 11 p15 5 15 3Search forStructuresSwiss modelDomainsInterProProtein families editD lactate dehydrogenase membrane binding nbsp crystal structure of d lactate dehydrogenase a peripheral membrane respiratory enzyme IdentifiersSymbolLact deh membPfamPF09330Pfam clanCL0277InterProIPR015409SCOP21f0x SCOPe SUPFAMAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summary lactate malate dehydrogenase NAD binding domainIdentifiersSymbolLdh 1 NPfamPF00056Pfam clanCL0063InterProIPR001236SCOP26ldh SCOPe SUPFAMAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summary lactate malate dehydrogenase alpha beta C terminal domainIdentifiersSymbolLdh 1 CPfamPF02866Pfam clanCL0341InterProIPR022383PROSITEPDOC00066SCOP26ldh SCOPe SUPFAMAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summary The family also contains L lactate dehydrogenases that catalyse the conversion of pyruvate to L lactate the last step in anaerobic glycolysis Malate dehydrogenases that catalyse the interconversion of malate to oxaloacetate and participate in the citric acid cycle and L 2 hydroxyisocaproate dehydrogenases are also members of the family The N terminus is a Rossmann NAD binding fold and the C terminus is an unusual alpha beta fold 7 8 Interactive pathway map editClick on genes proteins and metabolites below to link to respective articles 1 File nbsp nbsp alt Glycolysis and Gluconeogenesis edit Glycolysis and Gluconeogenesis edit The interactive pathway map can be edited at WikiPathways GlycolysisGluconeogenesis WP534 Enzyme regulation editThis protein may use the morpheein model of allosteric regulation 9 Ethanol induced hypoglycemia edit Ethanol is dehydrogenated to acetaldehyde by alcohol dehydrogenase and further into acetyl CoA by acetaldehyde dehydrogenase During this reaction 2 NADH are produced If large amounts of ethanol are present then large amounts of NADH are produced leading to a depletion of NAD Thus the conversion of pyruvate to lactate is increased due to the associated regeneration of NAD Therefore anion gap metabolic acidosis lactic acidosis may ensue in ethanol poisoning The increased NADH NAD ratio also can cause hypoglycemia in an otherwise fasting individual who has been drinking and is dependent on gluconeogenesis to maintain blood glucose levels Alanine and lactate are major gluconeogenic precursors that enter gluconeogenesis as pyruvate The high NADH NAD ratio shifts the lactate dehydrogenase equilibrium to lactate so that less pyruvate can be formed and therefore gluconeogenesis is impaired Substrate regulation edit LDH is also regulated by the relative concentrations of its substrates LDH becomes more active under periods of extreme muscular output due to an increase in substrates for the LDH reaction When skeletal muscles are pushed to produce high levels of power the demand for ATP in regards to aerobic ATP supply leads to an accumulation of free ADP AMP and Pi The subsequent glycolytic flux specifically production of pyruvate exceeds the capacity for pyruvate dehydrogenase and other shuttle enzymes to metabolize pyruvate The flux through LDH increases in response to increased levels of pyruvate and NADH to metabolize pyruvate into lactate 10 Transcriptional regulation edit LDH undergoes transcriptional regulation by PGC 1a PGC 1a regulates LDH by decreasing LDH A mRNA transcription and the enzymatic activity of pyruvate to lactate conversion 11 Genetics editThe M and H subunits are encoded by two different genes The M subunit is encoded by LDHA located on chromosome 11p15 4 Online Mendelian Inheritance in Man OMIM 150000 The H subunit is encoded by LDHB located on chromosome 12p12 2 p12 1 Online Mendelian Inheritance in Man OMIM 150100 A third isoform LDHC or LDHX is expressed only in the testis Online Mendelian Inheritance in Man OMIM 150150 its gene is likely a duplicate of LDHA and is also located on the eleventh chromosome 11p15 5 p15 3 The fourth isoform is localized in the peroxisome It is tetramer containing one LDHBx subunit which is also encoded by the LDHB gene The LDHBx protein is seven amino acids longer than the LDHB LDH H protein This amino acid extension is generated by functional translational readthrough 6 Mutations of the M subunit have been linked to the rare disease exertional myoglobinuria see OMIM article and mutations of the H subunit have been described but do not appear to lead to disease Mutations edit nbsp This is a mutant version of the LDH 5 enzyme which is usually found in skeletal muscleIn rare cases a mutation in the genes controlling the production of lactate dehydrogenase will lead to a medical condition known as lactate dehydrogenase deficiency Depending on which gene carries the mutation one of two types will occur either lactate dehydrogenase A deficiency also known as glycogen storage disease XI or lactate dehydrogenase B deficiency Both of these conditions affect how the body breaks down sugars primarily in certain muscle cells Lactate dehydrogenase A deficiency is caused by a mutation to the LDHA gene while lactate dehydrogenase B deficiency is caused by a mutation to the LDHB gene 12 This condition is inherited in an autosomal recessive pattern meaning that both parents must contribute a mutated gene in order for this condition to be expressed 13 A complete lactate dehydrogenase enzyme consists of four protein subunits 14 Since the two most common subunits found in lactate dehydrogenase are encoded by the LDHA and LDHB genes either variation of this disease causes abnormalities in many of the lactate dehydrogenase enzymes found in the body In the case of lactate dehydrogenase A deficiency mutations to the LDHA gene result in the production of an abnormal lactate dehydrogenase A subunit that cannot bind to the other subunits to form the complete enzyme This lack of a functional subunit reduces the amount of enzyme formed leading to an overall decrease in activity During the anaerobic phase of glycolysis the Cori cycle the mutated enzyme is unable to convert pyruvate into lactate to produce the extra energy the cells need Since this subunit has the highest concentration in the LDH enzymes found in the skeletal muscles which are the primary muscles responsible for movement high intensity physical activity will lead to an insufficient amount of energy being produced during this anaerobic phase 15 This in turn will cause the muscle tissue to weaken and eventually break down a condition known as rhabdomyolysis The process of rhabdomyolysis also releases myoglobin into the blood which will eventually end up in the urine and cause it to become red or brown another condition known as myoglobinuria 16 Some other common symptoms are exercise intolerance which consists of fatigue muscle pain and cramps during exercise and skin rashes 17 18 In severe cases myoglobinuria can damage the kidneys and lead to life threatening kidney failure 19 In order to obtain a definitive diagnosis a muscle biopsy may be performed to confirm low or absent LDH activity There is currently no specific treatment for this condition In the case of lactate dehydrogenase B deficiency mutations to the LDHB gene result in the production of an abnormal lactate dehydrogenase B subunit that cannot bind to the other subunits to form the complete enzyme As with lactate dehydrogenase A deficiency this mutation reduces the overall effectiveness in the enzyme 20 However there are some major differences between these two cases The first is the location where the condition manifests itself With lactate dehydrogenase B deficiency the highest concentration of B subunits can be found within the cardiac muscle or the heart Within the heart lactate dehydrogenase plays the role of converting lactate back into pyruvate so that the pyruvate can be used again to create more energy 21 With the mutated enzyme the overall rate of this conversion is decreased However unlike lactate dehydrogenase A deficiency this mutation does not appear to cause any symptoms or health problems linked to this condition 18 22 At the present moment it is unclear why this is the case Affected individuals are usually discovered only when routine blood tests indicate low LDH levels present within the blood Role in muscular fatigue editThe onset of acidosis during periods of intense exercise is commonly attributed to accumulation of hydrogens that are dissociated from lactate Previously lactic acid was thought to cause fatigue From this reasoning the idea of lactate production being a primary cause of muscle fatigue during exercise was widely adopted A closer mechanistic analysis of lactate production under anaerobic conditions shows that there is no biochemical evidence for the production of lactate through LDH contributing to acidosis While LDH activity is correlated to muscle fatigue 23 the production of lactate by means of the LDH complex works as a system to delay the onset of muscle fatigue George Brooks and Colleagues at UC Berkeley where the lactate shuttle was discovered showed that lactate was actually a metabolic fuel not a waste product or the cause of fatigue LDH works to prevent muscular failure and fatigue in multiple ways The lactate forming reaction generates cytosolic NAD which feeds into the glyceraldehyde 3 phosphate dehydrogenase reaction to help maintain cytosolic redox potential and promote substrate flux through the second phase of glycolysis to promote ATP generation This in effect provides more energy to contracting muscles under heavy workloads The production and removal of lactate from the cell also ejects a proton consumed in the LDH reaction the removal of excess protons produced in the wake of this fermentation reaction serves to act as a buffer system for muscle acidosis citation needed Once proton accumulation exceeds the rate of uptake in lactate production and removal through the LDH symport 24 muscular acidosis occurs Blood test editReference ranges for blood tests for lactate dehydrogenase Lower limit Upper limit Unit Comments50 25 150 25 U L0 4 26 1 7 26 mmol L1 8 27 3 4 27 µkat L lt 70 years old 27 On blood tests an elevated level of lactate dehydrogenase usually indicates tissue damage which has multiple potential causes reflecting its widespread tissue distribution Hemolytic anemia 28 Vitamin B12 deficiency anemia 28 Infections such as infectious mononucleosis meningitis encephalitis HIV AIDS It is notably increased in sepsis 28 Infarction such as bowel infarction myocardial infarction and lung infarction 28 Acute kidney disease 28 Acute liver disease 28 Rhabdomyolysis 29 Pancreatitis 28 Bone fractures 28 Cancers notably testicular cancer and lymphoma A high LDH after chemotherapy may indicate that it has not been successful 28 Severe shock 28 Hypoxia 28 Low and normal levels of LDH do not usually indicate any pathology 28 Low levels may be caused by large intake of vitamin C LDH is a protein that normally appears throughout the body in small amounts Testing in cancer edit nbsp Comparison of LDH activity in normal and cancerous cellsMany cancers can raise LDH levels so LDH may be used as a tumor marker but at the same time it is not useful in identifying a specific kind of cancer Measuring LDH levels can be helpful in monitoring treatment for cancer Noncancerous conditions that can raise LDH levels include heart failure hypothyroidism anemia pre eclampsia meningitis encephalitis acute pancreatitis HIV and lung or liver disease 30 Tissue breakdown releases LDH and therefore LDH can be measured as a surrogate for tissue breakdown e g hemolysis LDH is measured by the lactate dehydrogenase LDH test also known as the LDH test or lactic acid dehydrogenase test Comparison of the measured LDH values with the normal range help guide diagnosis 31 Hemolysis edit In medicine LDH is often used as a marker of tissue breakdown as LDH is abundant in red blood cells and can function as a marker for hemolysis A blood sample that has been handled incorrectly can show false positively high levels of LDH due to erythrocyte damage It can also be used as a marker of myocardial infarction Following a myocardial infarction levels of LDH peak at 3 4 days and remain elevated for up to 10 days In this way elevated levels of LDH where the level of LDH1 is higher than that of LDH2 i e the LDH Flip as normally in serum LDH2 is higher than LDH1 can be useful for determining whether a patient has had a myocardial infarction if they come to doctors several days after an episode of chest pain Tissue turnover edit Other uses are assessment of tissue breakdown in general this is possible when there are no other indicators of hemolysis It is used to follow up cancer especially lymphoma patients as cancer cells have a high rate of turnover with destroyed cells leading to an elevated LDH activity HIV edit LDH is often measured in HIV patients as a non specific marker for pneumonia due to Pneumocystis jirovecii PCP Elevated LDH in the setting of upper respiratory symptoms in a HIV patient suggests but is not diagnostic for PCP However in HIV positive patients with respiratory symptoms a very high LDH level gt 600 IU L indicated histoplasmosis 9 33 times more likely in a study of 120 PCP and 30 histoplasmosis patients 32 Testing in other body fluids editExudates and transudates edit Measuring LDH in fluid aspirated from a pleural effusion or pericardial effusion can help in the distinction between exudates actively secreted fluid e g due to inflammation or transudates passively secreted fluid due to a high hydrostatic pressure or a low oncotic pressure The usual criterion included in Light s criteria is that a ratio of pleural LDH to serum LDH greater than 0 6 33 or 2 3 the upper limit of the normal laboratory value for serum LDH 34 indicates an exudate while a ratio of less indicates a transudate Different laboratories have different values for the upper limit of serum LDH but examples include 200 35 and 300 35 IU L 36 In empyema the LDH levels in general will exceed 1000 IU L Meningitis and encephalitis edit High levels of lactate dehydrogenase in cerebrospinal fluid are often associated with bacterial meningitis 37 In the case of viral meningitis high LDH in general indicates the presence of encephalitis and poor prognosis In cancer treatment editLDH is involved in tumor initiation and metabolism Cancer cells rely on increased glycolysis resulting in increased lactate production in addition to aerobic respiration in the mitochondria even under oxygen sufficient conditions a process known as the Warburg effect 38 This state of fermentative glycolysis is catalyzed by the A form of LDH This mechanism allows tumorous cells to convert the majority of their glucose stores into lactate regardless of oxygen availability shifting use of glucose metabolites from simple energy production to the promotion of accelerated cell growth and replication LDH A and the possibility of inhibiting its activity has been identified as a promising target in cancer treatments focused on preventing carcinogenic cells from proliferating Chemical inhibition of LDH A has demonstrated marked changes in metabolic processes and overall survival of carcinoma cells Oxamate is a cytosolic inhibitor of LDH A that significantly decreases ATP production in tumorous cells as well as increasing production of reactive oxygen species ROS These ROS drive cancer cell proliferation by activating kinases that drive cell cycle progression growth factors at low concentrations 39 but can damage DNA through oxidative stress at higher concentrations Secondary lipid oxidation products can also inactivate LDH and impact its ability to regenerate NADH 40 directly disrupting the enzymes ability to convert lactate to pyruvate While recent studies have shown that LDH activity is not necessarily an indicator of metastatic risk 41 LDH expression can act as a general marker in the prognosis of cancers Expression of LDH5 and VEGF in tumors and the stroma has been found to be a strong prognostic factor for diffuse or mixed type gastric cancers 42 Prokaryotes editA cap membrane binding domain is found in prokaryotic lactate dehydrogenase This consists of a large seven stranded antiparallel beta sheet flanked on both sides by alpha helices It allows for membrane association 43 See also edit nbsp Biology portalDehydrogenase Erythrocyte lactate transporter defect formerly myopathy due to lactate transport defect Glycogen storage disease Lactate Metabolic myopathies OxidoreductaseReferences editThis article incorporates text from the public domain Pfam and InterPro IPR015409 Holmes RS Goldberg E October 2009 Computational analyses of mammalian lactate dehydrogenases human mouse opossum and platypus LDHs Computational Biology and Chemistry 33 5 379 85 doi 10 1016 j compbiolchem 2009 07 006 PMC 2777655 PMID 19679512 Wilks HM Holbrook JJ December 1988 A Specific Highly Active Malate Dehydrogenase by Redesign of a Lactate Dehydrogenase Framework Science 242 4885 1541 44 Bibcode 1988Sci 242 1541W doi 10 1126 science 3201242 PMID 3201242 Eventoff W Rossmann MG Taylor SS Torff HJ Meyer H Keil W Kiltz HH July 1977 Structural adaptations of lactate dehydrogenase isozymes Proceedings of the National Academy of Sciences of the United States of America 74 7 2677 81 Bibcode 1977PNAS 74 2677E doi 10 1073 pnas 74 7 2677 PMC 431242 PMID 197516 a b Zhang Y Chen K Sloan SA Bennett ML Scholze AR O Keeffe S et al September 2014 An RNA sequencing transcriptome and splicing database of glia neurons and vascular cells of the cerebral cortex The Journal of Neuroscience 34 36 11929 47 doi 10 1523 JNEUROSCI 1860 14 2014 PMC 4152602 PMID 25186741 Van Eerd JP Kreutzer EK 1996 Klinische Chemie voor Analisten deel 2 pp 138 139 ISBN 978 90 313 2003 5 a b Schueren F Lingner T George R Hofhuis J Gartner J Thoms S 2014 Peroxisomal lactate dehydrogenase is generated by translational readthrough in mammals eLife 3 e03640 doi 10 7554 eLife 03640 PMC 4359377 PMID 25247702 Chapman AD Cortes A Dafforn TR Clarke AR Brady RL 1999 Structural basis of substrate specificity in malate dehydrogenases crystal structure of a ternary complex of porcine cytoplasmic malate dehydrogenase alpha ketomalonate and tetrahydoNAD J Mol Biol 285 2 703 12 doi 10 1006 jmbi 1998 2357 PMID 10075524 Madern D 2002 Molecular evolution within the L malate and L lactate dehydrogenase super family J Mol Evol 54 6 825 40 Bibcode 2002JMolE 54 825M doi 10 1007 s00239 001 0088 8 PMID 12029364 S2CID 469660 Selwood T Jaffe EK March 2012 Dynamic dissociating homo oligomers and the control of protein function Arch Biochem Biophys 519 2 131 43 doi 10 1016 j abb 2011 11 020 PMC 3298769 PMID 22182754 Spriet LL Howlett RA Heigenhauser GJ 2000 An enzymatic approach to lactate production in human skeletal muscle during exercise Med Sci Sports Exerc 32 4 756 63 doi 10 1097 00005768 200004000 00007 PMID 10776894 Summermatter S Santos G Perez Schindler J Handschin C 2013 Skeletal muscle PGC 1a controls whole body lactate homeostasis through estrogen related receptor a dependent activation of LDH B and repression of LDH A Proc Natl Acad Sci U S A 110 21 8738 43 Bibcode 2013PNAS 110 8738S doi 10 1073 pnas 1212976110 PMC 3666691 PMID 23650363 Lactate dehydrogenase deficiency Genetics Home Reference 29 February 2016 Retrieved 2 March 2016 Diseases Metabolic Diseases Causes Inheritance Muscular Dystrophy Association 18 December 2015 Retrieved 2 March 2016 Millar DB Frattali V Willick GE June 1969 The quaternary structure of lactate dehydrogenase I The subunit molecular weight and the reversible association at acid pH Biochemistry 8 6 2416 21 doi 10 1021 bi00834a025 PMID 5816379 Kanno T Sudo K Maekawa M Nishimura Y Ukita M Fukutake K March 1988 Lactate dehydrogenase M subunit deficiency a new type of hereditary exertional myopathy Clinica Chimica Acta International Journal of Clinical Chemistry 173 1 89 98 doi 10 1016 0009 8981 88 90359 2 PMID 3383424 Myoglobinuria Rhabdomyolysis neuromuscular wustl edu Retrieved 2 March 2016 Hoffmann GF 1 January 2002 Inherited Metabolic Diseases Lippincott Williams amp Wilkins ISBN 9780781729000 a b Glycogenoses neuromuscular wustl edu Retrieved 2 March 2016 Glycogen storage disease XI Conditions GTR NCBI www ncbi nlm nih gov Retrieved 2 March 2016 LDHB gene Genetics Home Reference 29 February 2016 Retrieved 2 March 2016 Lactate Dehydrogenase Worthington Enzyme Manual www worthington biochem com Retrieved 2 March 2016 OMIM Entry 614128 LACTATE DEHYDROGENASE B DEFICIENCY LDHBD www omim org Retrieved 2 March 2016 Tesch P Sjodin B Thorstensson A Karlsson J 1978 Muscle fatigue and its relation to lactate accumulation and LDH activity in man Acta Physiol Scand 103 4 413 20 doi 10 1111 j 1748 1716 1978 tb06235 x PMID 716962 Juel C Klarskov C Nielsen JJ Krustrup P Mohr M Bangsbo J 2004 Effect of high intensity intermittent training on lactate and H release from human skeletal muscle Am J Physiol Endocrinol Metab 286 2 E245 51 CiteSeerX 10 1 1 336 372 doi 10 1152 ajpendo 00303 2003 PMID 14559724 a b Blood Test Results Normal Ranges Archived 2012 11 02 at the Wayback Machine Bloodbook Com a b Nohring FJ 2004 Langenscheidt Fachworterbuch Medizin kompakt Englisch englisch deutsch deutsch englisch 2nd ed Berlin Elsevier Urban amp FischerVerlag ISBN 978 3 437 15120 0 a b c Laborationslista Laboratory list Reference range list PDF Uppsala University Hospital 22 April 2008 Artnr 40284 Sj74a a b c d e f g h i j k l Lactate Dehydrogenase LD Lab Tests Online Retrieved 22 June 2018 Keltz E Khan FY Mann G October 2013 Rhabdomyolysis The role of diagnostic and prognostic factors Muscles Ligaments and Tendons Journal 3 4 303 312 doi 10 32098 mltj 04 2013 11 PMC 3940504 PMID 24596694 Stanford Cancer Center Cancer Diagnosis Understanding Cancer Understanding Cancer Stanford Medicine Lactate dehydrogenase test MedlinePlus Medical Encyclopedia MedlinePlus U S National Library of Medicine Butt AA Michaels S Greer D Clark R Kissinger P Martin DH July 2002 Serum LDH level as a clue to the diagnosis of histoplasmosis AIDS Read 12 7 317 21 PMID 12161854 Heffner JE Brown LK Barbieri CA April 1997 Diagnostic value of tests that discriminate between exudative and transudative pleural effusions Primary Study Investigators Chest 111 4 970 80 doi 10 1378 chest 111 4 970 PMID 9106577 Light RW Macgregor MI Luchsinger PC Ball WC October 1972 Pleural effusions the diagnostic separation of transudates and exudates Ann Intern Med 77 4 507 13 doi 10 7326 0003 4819 77 4 507 PMID 4642731 a b Joseph J Badrinath P Basran GS Sahn SA November 2001 Is the pleural fluid transudate or exudate A revisit of the diagnostic criteria Thorax 56 11 867 70 doi 10 1136 thorax 56 11 867 PMC 1745948 PMID 11641512 Joseph J Badrinath P Basran GS Sahn SA March 2002 Is albumin gradient or fluid to serum albumin ratio better than the pleural fluid lactate dehydroginase in the diagnostic of separation of pleural effusion BMC Pulm Med 2 1 doi 10 1186 1471 2466 2 1 PMC 101409 PMID 11914151 Stein JH 1998 Internal Medicine Elsevier Health Sciences pp 1408 ISBN 978 0 8151 8698 4 Retrieved 12 August 2013 Warburg O 1956 On the origin of cancer cells Science 123 3191 309 14 Bibcode 1956Sci 123 309W doi 10 1126 science 123 3191 309 PMID 13298683 Irani K Xia Y Zweier JL Sollott SJ Der CJ Fearon ER Sundaresan M Finkel T Goldschmidt Clermont PJ 1997 Mitogenic signaling mediated by oxidants in Ras transformed fibroblasts Science 275 5306 1649 52 doi 10 1126 science 275 5306 1649 PMID 9054359 S2CID 19733670 Ramanathan R Mancini RA Suman SP Beach CM 2014 Covalent Binding of 4 Hydroxy 2 nonenal to Lactate Dehydrogenase Decreases NADH Formation and Metmyoglobin Reducing Activity J Agric Food Chem 62 9 2112 7 doi 10 1021 jf404900y PMID 24552270 Xu HN Kadlececk S Profka H Glickson JD Rizi R Li LZ 2014 Is Higher Lactate an Indicator of Tumor Metastatic Risk A Pilot MRS Study Using Hyperpolarized 13 C Pyruvate Acad Radiol 21 2 223 31 doi 10 1016 j acra 2013 11 014 PMC 4169113 PMID 24439336 Kim HS Lee HE Yang HK Kim WH 2014 High lactate dehydrogenase 5 expression correlates with high tumoral and stromal vascular endothelial growth factor expression in gastric cancer Pathobiology 81 2 78 85 doi 10 1159 000357017 PMID 24401755 Dym O Pratt EA Ho C Eisenberg D August 2000 The crystal structure of D lactate dehydrogenase a peripheral membrane respiratory enzyme Proc Natl Acad Sci U S A 97 17 9413 8 Bibcode 2000PNAS 97 9413D doi 10 1073 pnas 97 17 9413 PMC 16878 PMID 10944213 Further reading editJohnson WT Canfield WK 1985 Intestinal absorption and excretion of zinc in streptozotocin diabetic rats as affected by dietary zinc and protein J Nutr 115 9 1217 27 doi 10 1093 jn 115 9 1217 PMID 3897486 Ein SH Mancer K Adeyemi SD 1985 Malignant sacrococcygeal teratoma endodermal sinus yolk sac tumor in infants and children a 32 year review J Pediatr Surg 20 5 473 7 doi 10 1016 s0022 3468 85 80468 1 PMID 3903096 Azuma M Shi M Danenberg KD Gardner H Barrett C Jacques CJ Sherod A Iqbal S El Khoueiry A Yang D Zhang W Danenberg PV Lenz HJ 2007 Serum lactate dehydrogenase levels and glycolysis significantly correlate with tumor VEGFA and VEGFR expression in metastatic CRC patients Pharmacogenomics 8 12 1705 13 doi 10 2217 14622416 8 12 1705 PMID 18086000 Masepohl B Klipp W Puhler A 1988 Genetic characterization and sequence analysis of the duplicated nifA nifB gene region of Rhodobacter capsulatus Mol Gen Genet 212 1 27 37 doi 10 1007 bf00322441 PMID 2836706 S2CID 21009965 Galardo MN Regueira M Riera MF Pellizzari EH Cigorraga SB Meroni SB 2014 Lactate Regulates Rat Male Germ Cell Function through Reactive Oxygen Species PLOS ONE 9 1 e88024 Bibcode 2014PLoSO 988024G doi 10 1371 journal pone 0088024 PMC 3909278 PMID 24498241 Tesch P Sjodin B Thorstensson A Karlsson J 1978 Muscle fatigue and its relation to lactate accumulation and LDH activity in man Acta Physiol Scand 103 4 413 20 doi 10 1111 j 1748 1716 1978 tb06235 x PMID 716962 Beck O Jernstrom B Martinez M Repke DB 1988 In vitro study of the aromatic hydroxylation of 1 methyltetrahydro beta carboline methtryptoline in rat Chem Biol Interact 65 1 97 106 doi 10 1016 0009 2797 88 90034 8 PMID 3345575 Summermatter S Santos G Perez Schindler J Handschin C 2013 Skeletal muscle PGC 1a controls whole body lactate homeostasis through estrogen related receptor a dependent activation of LDH B and repression of LDH A Proc Natl Acad Sci U S A 110 21 8738 43 Bibcode 2013PNAS 110 8738S doi 10 1073 pnas 1212976110 PMC 3666691 PMID 23650363 Robergs RA Ghiasvand F Parker D 2004 Biochemistry of exercise induced metabolic acidosis Am J Physiol Regul Integr Comp Physiol 287 3 R502 16 doi 10 1152 ajpregu 00114 2004 PMID 15308499 S2CID 2745168 Kresge N Simoni RD Hill RL 2005 Otto Fritz Meyerhof and the elucidation of the glycolytic pathway J Biol Chem 280 4 e3 doi 10 1016 S0021 9258 20 76366 0 PMID 15665335 External links edit nbsp Media related to Lactate dehydrogenase at Wikimedia Commons Retrieved from https en wikipedia org w index php title Lactate dehydrogenase amp oldid 1194967670, wikipedia, 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