This article is about the family of mammalian albumin proteins. For the human variant, see Human serum albumin. For the cow variant, see Bovine serum albumin. For the egg white protein, see Conalbumin.
Serum albumin is produced by the liver, occurs dissolved in blood plasma and is the most abundant blood protein in mammals. Albumin is essential for maintaining the oncotic pressure needed for proper distribution of body fluids between blood vessels and body tissues; without albumin, the high pressure in the blood vessels would force more fluids out into the tissues. It also acts as a plasma carrier by non-specifically binding several hydrophobicsteroid hormones and as a transport protein for hemin and fatty acids. Too much or too little circulating serum albumin may be harmful. Albumin in the urine usually denotes the presence of kidney disease. Occasionally albumin appears in the urine of normal persons following long periods of standing (postural albuminuria).
Albumin functions primarily as a carrier protein for steroids, fatty acids, and thyroid hormones in the blood and plays a major role in stabilizing extracellular fluid volume by contributing to oncotic pressure (known also as colloid osmotic pressure) of plasma.
Because smaller animals (for example rats) function at a lower blood pressure, they need less oncotic pressure to balance this[citation needed], and thus need less albumin to maintain proper fluid distribution.
As an anionic protein, albumin binds readily to calcium in blood serum and contributes greatly to plasma calcium levels. As such, in clinical applications it is necessary to adjust serum total calcium concentration upward or downward if hypoalbuminemia or hyperalbuminemia is present, respectively (measured serum total calcium decreases by 0.8 mg/dL per unit decrease in albumin concentration below 4 g/dL).[5][6]
Synthesisedit
Albumin is synthesized in the liver as preproalbumin which has an N-terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum. The product, proalbumin, is in turn cleaved in the Golgi vesicles to produce the secreted albumin.[4]
Propertiesedit
Albumin is a globular, water-soluble, un-glycosylated serum protein of approximate molecular weight of 65,000 daltons.
Albumin (when ionized in water at pH 7.4, as found in the body) is negatively charged. The glomerular basement membrane is also negatively charged in the body; some studies suggest that this prevents the filtration of albumin in the urine. According to this theory, that charge plays a major role in the selective exclusion of albumin from the glomerular filtrate. A defect in this property results in nephrotic syndrome leading to albumin loss in the urine. Nephrotic syndrome patients are sometimes given albumin to replace the lost albumin.
The general structure of albumin is characterized by several long α helices allowing it to maintain a relatively static shape, which is essential for regulating blood pressure.
Serum albumin contains eleven distinct binding domains for hydrophobic compounds. One hemin and six long-chain fatty acids can bind to serum albumin at the same time.[7]
Bovine serum albumin, or BSA, is commonly used in immunodiagnostic procedures, clinical chemistry reagents, cell culture media, protein chemistry research (including venom toxicity), and molecular biology laboratories (usually to leverage its non-specific protein binding properties).
^Sugio S, Kashima A, Mochizuki S, Noda M, Kobayashi K (June 1999). "Crystal structure of human serum albumin at 2.5 A resolution". Protein Engineering. 12 (6): 439–46. doi:10.1093/protein/12.6.439. PMID 10388840.
^Hawkins JW, Dugaiczyk A (1982). "The human serum albumin gene: structure of a unique locus". Gene. 19 (1): 55–8. doi:10.1016/0378-1119(82)90188-3. PMID 6292049.
^Harper ME, Dugaiczyk A (July 1983). "Linkage of the evolutionarily-related serum albumin and alpha-fetoprotein genes within q11-22 of human chromosome 4". American Journal of Human Genetics. 35 (4): 565–72. PMC1685723. PMID 6192711.
^ ab"Entrez Gene: albumin". U.S. National Library of Medicine.
^Goyal A, Anastasopoulou C, Ngu M, Singh S (8 May 2022). "Hypocalcemia". StatPearls. StatPearls Publishing LLC. PMID 28613662.
^Holliman K (March 2012). "Diagnosing a disorder with few symptoms". ACP Internist. American College of Physicians. Retrieved 13 June 2022.
^Zunszain PA, Ghuman J, Komatsu T, Tsuchida E, Curry S (July 2003). "Crystal structural analysis of human serum albumin complexed with hemin and fatty acid". BMC Structural Biology. 3: 6. doi:10.1186/1472-6807-3-6. PMC166163. PMID 12846933.
External linksedit
RCSB Protein Data Bank : Molecule of the Month – Serum Albumin
Albumin binding prediction
Overview of all the structural information available in the PDB for UniProt: P02768 (Human Serum albumin) at the PDBe-KB.
February 15, 2024
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This article is about the family of mammalian albumin proteins For the human variant see Human serum albumin For the cow variant see Bovine serum albumin For the egg white protein see Conalbumin Serum albumin often referred to simply as blood albumin is an albumin a type of globular protein found in vertebrate blood Human serum albumin is encoded by the ALB gene 2 3 4 Other mammalian forms such as bovine serum albumin are chemically similar Serum albumin familyStructure of human serum albumin 1 IdentifiersSymbolSerum albuminPfamPF00273Pfam clanCL0282InterProIPR014760SMARTSM00103PROSITEPS51438SCOP21ao6 SCOPe SUPFAMAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryPDB1ao6 1bj5 1bke 1bm0 1e78 1e7a 1e7b 1e7c 1e7e 1e7f 1e7g 1e7h 1e7i 1gni 1gnj 1h9z 1ha2 1hk1 1hk2 1hk3 1hk4 1hk5 1j78 1j7e 1kw2 1kxp 1lot 1ma9 1n5u 1o9x 1tf0 1uor 1ysx 2bx8 2bxa 2bxb 2bxc 2bxd 2bxe 2bxf 2bxg 2bxh 2bxi 2bxk 2bxl 2bxm 2bxn 2bxo 2bxp 2bxq 2i2z 2i30 2vdb 2vue 2vuf 3b9l 3b9m Serum albumin is produced by the liver occurs dissolved in blood plasma and is the most abundant blood protein in mammals Albumin is essential for maintaining the oncotic pressure needed for proper distribution of body fluids between blood vessels and body tissues without albumin the high pressure in the blood vessels would force more fluids out into the tissues It also acts as a plasma carrier by non specifically binding several hydrophobic steroid hormones and as a transport protein for hemin and fatty acids Too much or too little circulating serum albumin may be harmful Albumin in the urine usually denotes the presence of kidney disease Occasionally albumin appears in the urine of normal persons following long periods of standing postural albuminuria Contents 1 Function 2 Synthesis 3 Properties 4 Structure 5 Types 6 See also 7 References 8 External linksFunction editAlbumin functions primarily as a carrier protein for steroids fatty acids and thyroid hormones in the blood and plays a major role in stabilizing extracellular fluid volume by contributing to oncotic pressure known also as colloid osmotic pressure of plasma Because smaller animals for example rats function at a lower blood pressure they need less oncotic pressure to balance this citation needed and thus need less albumin to maintain proper fluid distribution As an anionic protein albumin binds readily to calcium in blood serum and contributes greatly to plasma calcium levels As such in clinical applications it is necessary to adjust serum total calcium concentration upward or downward if hypoalbuminemia or hyperalbuminemia is present respectively measured serum total calcium decreases by 0 8 mg dL per unit decrease in albumin concentration below 4 g dL 5 6 Synthesis editAlbumin is synthesized in the liver as preproalbumin which has an N terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum The product proalbumin is in turn cleaved in the Golgi vesicles to produce the secreted albumin 4 Properties editAlbumin is a globular water soluble un glycosylated serum protein of approximate molecular weight of 65 000 daltons Albumin when ionized in water at pH 7 4 as found in the body is negatively charged The glomerular basement membrane is also negatively charged in the body some studies suggest that this prevents the filtration of albumin in the urine According to this theory that charge plays a major role in the selective exclusion of albumin from the glomerular filtrate A defect in this property results in nephrotic syndrome leading to albumin loss in the urine Nephrotic syndrome patients are sometimes given albumin to replace the lost albumin Structure editMain article Albumin The general structure of albumin is characterized by several long a helices allowing it to maintain a relatively static shape which is essential for regulating blood pressure Serum albumin contains eleven distinct binding domains for hydrophobic compounds One hemin and six long chain fatty acids can bind to serum albumin at the same time 7 Types editSerum albumin is widely distributed in mammals The human version is human serum albumin Bovine serum albumin or BSA is commonly used in immunodiagnostic procedures clinical chemistry reagents cell culture media protein chemistry research including venom toxicity and molecular biology laboratories usually to leverage its non specific protein binding properties See also editBlood plasma fractionation Bovine serum albumin Chromatography in blood processing Human serum albumin Lactalbumin OvalbuminReferences edit Sugio S Kashima A Mochizuki S Noda M Kobayashi K June 1999 Crystal structure of human serum albumin at 2 5 A resolution Protein Engineering 12 6 439 46 doi 10 1093 protein 12 6 439 PMID 10388840 Hawkins JW Dugaiczyk A 1982 The human serum albumin gene structure of a unique locus Gene 19 1 55 8 doi 10 1016 0378 1119 82 90188 3 PMID 6292049 Harper ME Dugaiczyk A July 1983 Linkage of the evolutionarily related serum albumin and alpha fetoprotein genes within q11 22 of human chromosome 4 American Journal of Human Genetics 35 4 565 72 PMC 1685723 PMID 6192711 a b Entrez Gene albumin U S National Library of Medicine Goyal A Anastasopoulou C Ngu M Singh S 8 May 2022 Hypocalcemia StatPearls StatPearls Publishing LLC PMID 28613662 Holliman K March 2012 Diagnosing a disorder with few symptoms ACP Internist American College of Physicians Retrieved 13 June 2022 Zunszain PA Ghuman J Komatsu T Tsuchida E Curry S July 2003 Crystal structural analysis of human serum albumin complexed with hemin and fatty acid BMC Structural Biology 3 6 doi 10 1186 1472 6807 3 6 PMC 166163 PMID 12846933 External links editRCSB Protein Data Bank Molecule of the Month Serum Albumin Albumin binding prediction Overview of all the structural information available in the PDB for UniProt P02768 Human Serum albumin at the PDBe KB Retrieved from https en wikipedia org w index php title Serum albumin amp oldid 1188111218, wikipedia, wiki, book, books, library,
