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Cystine

February 15, 2024

Not to be confused with cytosine, cysteine, cytisine, or cytidine.

Cystine is the oxidized derivative of the amino acid cysteine and has the formula (SCH2CH(NH2)CO2H)2. It is a white solid that is poorly soluble in water. As a residue in proteins, cystine serves two functions: a site of redox reactions and a mechanical linkage that allows proteins to retain their three-dimensional structure.[1]

Cystine
Identifiers
  • 56-89-3 Y
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:35492 Y
ChEMBL
  • ChEMBL366563 Y
ChemSpider
  • 575 Y
ECHA InfoCard 100.000.270
  • 5413
KEGG
  • C01420 Y
  • 67678
UNII
  • 48TCX9A1VT Y
  • DTXSID2046418
  • InChI=1S/C6H12N2O4S2/c7-3(5(9)10)1-13-14-2-4(8)6(11)12/h3-4H,1-2,7-8H2,(H,9,10)(H,11,12) Y
    Key: LEVWYRKDKASIDU-UHFFFAOYSA-N Y
  • InChI=1/C6H12N2O4S2/c7-3(5(9)10)1-13-14-2-4(8)6(11)12/h3-4H,1-2,7-8H2,(H,9,10)(H,11,12)
    Key: LEVWYRKDKASIDU-UHFFFAOYAA
  • C(C(C(=O)O)N)SSCC(C(=O)O)N
Properties
C6H12N2O4S2
Molar mass 240.29 g·mol−1
Hazards
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)

Formation and reactions edit

Structure edit

Cystine is the disulfide derived from the amino acid cysteine. The conversion can be viewed as an oxidation:

2 HO2CCH(NH2)CH2SH + 0.5 O2 → (HO2CCH(NH2)CH2S)2 + H2O

Cystine contains a disulfide bond, two amine groups, and two carboxylic acid groups. As for other amino acids, the amine and carboxylic acid groups exist in rapid equilibrium with the ammonium-carboxylate tautomer. The great majority of the literature concerns the l,l-cystine, derived from l-cysteine. Other isomers include d,d-cystine and the meso isomer d,l-cystine, neither of which is biologically significant.

Occurrence edit

Cystine is common in many foods such as eggs, meat, dairy products, and whole grains as well as skin, horns and hair. It was not recognized as being derived of proteins until it was isolated from the horn of a cow in 1899.[2] Human hair and skin contain approximately 10–14% cystine by mass.[3]

History edit

Cystine was discovered in 1810 by the English chemist William Hyde Wollaston, who called it "cystic oxide".[4] In 1833, the Swedish chemist Jöns Jacob Berzelius named the amino acid "cystine".[5] The Norwegian chemist Christian J. Thaulow determined, in 1838, the empirical formula of cystine.[6] In 1884, the German chemist Eugen Baumann found that when cystine was treated with a reducing agent, cystine revealed itself to be a dimer of a monomer which he named "cysteïne".[7] In 1899, cystine was first isolated from protein (horn tissue) by the Swedish chemist Karl A. H. Mörner (1855-1917).[8] The chemical structure of cystine was determined by synthesis in 1903 by the German chemist Emil Erlenmeyer.[9][10][11]

Redox edit

It is formed from the oxidation of two cysteine molecules, which results in the formation of a disulfide bond. In cell biology, cystine residues (found in proteins) only exist in non-reductive (oxidative) organelles, such as the secretory pathway (endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles) and extracellular spaces (e.g., extracellular matrix). Under reductive conditions (in the cytoplasm, nucleus, etc.) cysteine is predominant. The disulfide link is readily reduced to give the corresponding thiol cysteine. Typical thiols for this reaction are mercaptoethanol and dithiothreitol:

(SCH2CH(NH2)CO2H)2 + 2 RSH → 2 HSCH2CH(NH2)CO2H + RSSR

Because of the facility of the thiol-disulfide exchange, the nutritional benefits and sources of cystine are identical to those for the more-common cysteine. Disulfide bonds cleave more rapidly at higher temperatures.[12]

Cystine-based disorders edit

 
Comparison of different types of urinary crystals.

The presence of cystine in urine is often indicative of amino acid reabsorption defects. Cystinuria has been reported to occur in dogs.[13] In humans the excretion of high levels of cystine crystals can be indicative of cystinosis, a rare genetic disease. Cystine stones account for about 1-2% of kidney stone disease in adults.[14][15]

Biological transport edit

Cystine serves as a substrate for the cystine-glutamate antiporter. This transport system, which is highly specific for cystine and glutamate, increases the concentration of cystine inside the cell. In this system, the anionic form of cystine is transported in exchange for glutamate. Cystine is quickly reduced to cysteine.[citation needed] Cysteine prodrugs, e.g. acetylcysteine, induce release of glutamate into the extracellular space.

Nutritional supplements edit

Cysteine supplements are sometimes marketed as anti-aging products with claims of improved skin elasticity.[citation needed] Cysteine is more easily absorbed by the body than cystine, so most supplements contain cysteine rather than cystine. N-acetyl-cysteine (NAC) is better absorbed than other cysteine or cystine supplements.

See also edit

References edit

  1. ^ Nelson, D. L.; Cox, M. M. (2000) Lehninger, Principles of Biochemistry. 3rd Ed. Worth Publishing: New York. ISBN 1-57259-153-6.
  2. ^ "cystine". Encyclopædia Britannica. 2007. Encyclopædia Britannica Online. 27 July 2007
  3. ^ Gortner, R. A.; Hoffman, W. F. (1925). "l-Cystine". Organic Syntheses. 5: 39.
  4. ^ Wollaston, William Hyde (1810). "On cystic oxide, a new species of urinary calculus". Philosophical Transactions of the Royal Society of London. 100: 223–230. On p. 227, Wollaston named cystine "cystic oxide".
  5. ^ Berzelius, J.J.; Esslinger, Me., trans. (1833). Traité de Chimie (in French). Vol. 7. Paris, France: Didot Frères. p. 424.{{cite book}}: CS1 maint: multiple names: authors list (link) From p. 424: "10. Cystine. Cette substance a été découverte dans les calculs urinaires par Wollaston, […] je me suis donc permis de changer le nom qu'avait proposé cet homme distingué." (10. Cystine. This substance was discovered in urinary calculi by Wollaston, who gave it the name of "cystic oxide" because it dissolves as much in acids as in alkalis, and it resembles, in this respect, some metallic oxides; but, in a way, the reason [that was] alleged to justify it is not valid: I have therefore taken the liberty of changing the name that this distinguished man had proposed.)
  6. ^ Thaulow, C. J. (1838). "Sur la composition de la cystine" [On the composition of cystine]. Journal de Pharmacie (in French). 24: 629–632.
  7. ^ Baumann, E. (1884). "Ueber Cystin und Cysteïn" [On cystine and cysteine]. Zeitschrift für physiologische Chemie (in German). 8: 299–305. From pp. 301-302: "Die Analyse der Substanz ergibt Werthe, welche den vom Cystin (C6H12N2S2O4) verlangten sich nähern, […] nenne ich dieses Reduktionsprodukt des Cystins: Cysteïn." (Analysis of the substance [cysteine] reveals values which approximate those [that are] required by cystine (C6H12N2S2O4), however the new base [cysteine] can clearly be recognized as a reduction product of cystine, to which the [empirical] formula C3H7NSO2, [which had] previously [been] ascribed to cystine, is [now] ascribed. In order to indicate the relationships of this substance to cystine, I name this reduction product of cystine: "cysteïne".) Note: Baumann's proposed structures for cysteine and cystine (see p.302) are incorrect: for cysteine, he proposed CH3CNH2(SH)COOH .
  8. ^ Mörner, K. A. H. (1899). "Cystin, ein Spaltungsprodukt der Hornsubstanz" [Cystine, a cleavage product of horn tissue]. Hoppe-Seyler's Zeitschrift für Physiologische Chemie (in German). 28 (5–6): 595–615. doi:10.1515/bchm2.1899.28.5-6.595.
  9. ^ Erlenmeyer, Emil (1903). "Synthese des Cystins" [Synthesis of cystine]. Berichte der Deutschen Chemischen Gesellschaft (in German). 36 (3): 2720–2722. doi:10.1002/cber.19030360320.
  10. ^ Erlenmeyer, E. jun.; Stoop, F. (1904). "Ueber die Synthese einiger α-Amido-β-hydroxysäuren. 2. Ueber die Synthese der Serins und Cystins" [On the synthesis of some α-amido-β-hydroxy acids. 2. On the synthesis of serine and cystine.]. Annalen der Chemie (in German). 337: 236–263. doi:10.1002/jlac.19043370205. Discussion of the synthesis of cystine begins on p. 241.
  11. ^ Erlenmeyer's findings regarding the structure of cystine were confirmed in 1908 by Fischer and Raske. See: Fischer, Emil; Raske, Karl (1908). "Verwandlung des l-Serines in aktives natürliches Cystin" [Conversion of l-serine into [optically] active natural cystine]. Berichte der Deutschen Chemischen Gesellschaft (in German). 41: 893–897. doi:10.1002/cber.190804101169.
  12. ^ Aslaksena, M.A.; Romarheima, O.H.; Storebakkena, T.; Skrede, A. (28 June 2006). "Evaluation of content and digestibility of disulfide bonds and free thiols in unextruded and extruded diets containing fish meal and soybean protein sources". Animal Feed Science and Technology. 128 (3–4): 320–330. doi:10.1016/j.anifeedsci.2005.11.008.
  13. ^ Gahl, William A.; Thoene, Jess G.; Schneider, Jerry A. (2002). "Cystinosis". New England Journal of Medicine. 347 (2): 111–121. doi:10.1056/NEJMra020552. PMID 12110740.
  14. ^ Frassetto L, Kohlstadt I (2011). "Treatment and prevention of kidney stones: an update". Am Fam Physician. 84 (11): 1234–42. PMID 22150656.
  15. ^ "Cystine stones". UpToDate. from the original on 26 February 2014. Retrieved 20 February 2014.

External links edit

  •   Media related to Cystine at Wikimedia Commons

February 15, 2024
cystine, confused, with, cytosine, cysteine, cytisine, cytidine, oxidized, derivative, amino, acid, cysteine, formula, sch2ch, co2h, white, solid, that, poorly, soluble, water, residue, proteins, cystine, serves, functions, site, redox, reactions, mechanical, . Not to be confused with cytosine cysteine cytisine or cytidine Cystine is the oxidized derivative of the amino acid cysteine and has the formula SCH2CH NH2 CO2H 2 It is a white solid that is poorly soluble in water As a residue in proteins cystine serves two functions a site of redox reactions and a mechanical linkage that allows proteins to retain their three dimensional structure 1 Cystine IdentifiersCAS Number 56 89 3 Y3D model JSmol Interactive imageChEBI CHEBI 35492 YChEMBL ChEMBL366563 YChemSpider 575 YECHA InfoCard 100 000 270IUPHAR BPS 5413KEGG C01420 YPubChem CID 67678UNII 48TCX9A1VT YCompTox Dashboard EPA DTXSID2046418InChI InChI 1S C6H12N2O4S2 c7 3 5 9 10 1 13 14 2 4 8 6 11 12 h3 4H 1 2 7 8H2 H 9 10 H 11 12 YKey LEVWYRKDKASIDU UHFFFAOYSA N YInChI 1 C6H12N2O4S2 c7 3 5 9 10 1 13 14 2 4 8 6 11 12 h3 4H 1 2 7 8H2 H 9 10 H 11 12 Key LEVWYRKDKASIDU UHFFFAOYAASMILES C C C O O N SSCC C O O NPropertiesChemical formula C 6H 12N 2O 4S 2Molar mass 240 29 g mol 1HazardsSafety data sheet SDS External MSDSExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Contents 1 Formation and reactions 1 1 Structure 1 2 Occurrence 1 3 History 1 4 Redox 1 5 Cystine based disorders 2 Biological transport 3 Nutritional supplements 4 See also 5 References 6 External linksFormation and reactions editStructure edit Cystine is the disulfide derived from the amino acid cysteine The conversion can be viewed as an oxidation 2 HO2CCH NH2 CH2SH 0 5 O2 HO2CCH NH2 CH2S 2 H2OCystine contains a disulfide bond two amine groups and two carboxylic acid groups As for other amino acids the amine and carboxylic acid groups exist in rapid equilibrium with the ammonium carboxylate tautomer The great majority of the literature concerns the l l cystine derived from l cysteine Other isomers include d d cystine and the meso isomer d l cystine neither of which is biologically significant Occurrence edit Cystine is common in many foods such as eggs meat dairy products and whole grains as well as skin horns and hair It was not recognized as being derived of proteins until it was isolated from the horn of a cow in 1899 2 Human hair and skin contain approximately 10 14 cystine by mass 3 History edit Cystine was discovered in 1810 by the English chemist William Hyde Wollaston who called it cystic oxide 4 In 1833 the Swedish chemist Jons Jacob Berzelius named the amino acid cystine 5 The Norwegian chemist Christian J Thaulow determined in 1838 the empirical formula of cystine 6 In 1884 the German chemist Eugen Baumann found that when cystine was treated with a reducing agent cystine revealed itself to be a dimer of a monomer which he named cysteine 7 In 1899 cystine was first isolated from protein horn tissue by the Swedish chemist Karl A H Morner 1855 1917 8 The chemical structure of cystine was determined by synthesis in 1903 by the German chemist Emil Erlenmeyer 9 10 11 Redox edit It is formed from the oxidation of two cysteine molecules which results in the formation of a disulfide bond In cell biology cystine residues found in proteins only exist in non reductive oxidative organelles such as the secretory pathway endoplasmic reticulum Golgi apparatus lysosomes and vesicles and extracellular spaces e g extracellular matrix Under reductive conditions in the cytoplasm nucleus etc cysteine is predominant The disulfide link is readily reduced to give the corresponding thiol cysteine Typical thiols for this reaction are mercaptoethanol and dithiothreitol SCH2CH NH2 CO2H 2 2 RSH 2 HSCH2CH NH2 CO2H RSSRBecause of the facility of the thiol disulfide exchange the nutritional benefits and sources of cystine are identical to those for the more common cysteine Disulfide bonds cleave more rapidly at higher temperatures 12 Cystine based disorders edit nbsp Comparison of different types of urinary crystals The presence of cystine in urine is often indicative of amino acid reabsorption defects Cystinuria has been reported to occur in dogs 13 In humans the excretion of high levels of cystine crystals can be indicative of cystinosis a rare genetic disease Cystine stones account for about 1 2 of kidney stone disease in adults 14 15 Biological transport editCystine serves as a substrate for the cystine glutamate antiporter This transport system which is highly specific for cystine and glutamate increases the concentration of cystine inside the cell In this system the anionic form of cystine is transported in exchange for glutamate Cystine is quickly reduced to cysteine citation needed Cysteine prodrugs e g acetylcysteine induce release of glutamate into the extracellular space Nutritional supplements editThis article is missing information about hair growth supplements Please expand the article to include this information Further details may exist on the talk page November 2022 Cysteine supplements are sometimes marketed as anti aging products with claims of improved skin elasticity citation needed Cysteine is more easily absorbed by the body than cystine so most supplements contain cysteine rather than cystine N acetyl cysteine NAC is better absorbed than other cysteine or cystine supplements See also editLanthionine similar with mono sulfide link Protein tertiary structure Sullivan reaction CystinosisReferences edit Nelson D L Cox M M 2000 Lehninger Principles of Biochemistry 3rd Ed Worth Publishing New York ISBN 1 57259 153 6 cystine Encyclopaedia Britannica 2007 Encyclopaedia Britannica Online 27 July 2007 Gortner R A Hoffman W F 1925 l Cystine Organic Syntheses 5 39 Wollaston William Hyde 1810 On cystic oxide a new species of urinary calculus Philosophical Transactions of the Royal Society of London 100 223 230 On p 227 Wollaston named cystine cystic oxide Berzelius J J Esslinger Me trans 1833 Traite de Chimie in French Vol 7 Paris France Didot Freres p 424 a href Template Cite book html title Template Cite book cite book a CS1 maint multiple names authors list link From p 424 10 Cystine Cette substance a ete decouverte dans les calculs urinaires par Wollaston je me suis donc permis de changer le nom qu avait propose cet homme distingue 10 Cystine This substance was discovered in urinary calculi by Wollaston who gave it the name of cystic oxide because it dissolves as much in acids as in alkalis and it resembles in this respect some metallic oxides but in a way the reason that was alleged to justify it is not valid I have therefore taken the liberty of changing the name that this distinguished man had proposed Thaulow C J 1838 Sur la composition de la cystine On the composition of cystine Journal de Pharmacie in French 24 629 632 Baumann E 1884 Ueber Cystin und Cystein On cystine and cysteine Zeitschrift fur physiologische Chemie in German 8 299 305 From pp 301 302 Die Analyse der Substanz ergibt Werthe welche den vom Cystin C6H12N2S2O4 verlangten sich nahern nenne ich dieses Reduktionsprodukt des Cystins Cystein Analysis of the substance cysteine reveals values which approximate those that are required by cystine C6H12N2S2O4 however the new base cysteine can clearly be recognized as a reduction product of cystine to which the empirical formula C3H7NSO2 which had previously been ascribed to cystine is now ascribed In order to indicate the relationships of this substance to cystine I name this reduction product of cystine cysteine Note Baumann s proposed structures for cysteine and cystine see p 302 are incorrect for cysteine he proposed CH3CNH2 SH COOH Morner K A H 1899 Cystin ein Spaltungsprodukt der Hornsubstanz Cystine a cleavage product of horn tissue Hoppe Seyler s Zeitschrift fur Physiologische Chemie in German 28 5 6 595 615 doi 10 1515 bchm2 1899 28 5 6 595 Erlenmeyer Emil 1903 Synthese des Cystins Synthesis of cystine Berichte der Deutschen Chemischen Gesellschaft in German 36 3 2720 2722 doi 10 1002 cber 19030360320 Erlenmeyer E jun Stoop F 1904 Ueber die Synthese einiger a Amido b hydroxysauren 2 Ueber die Synthese der Serins und Cystins On the synthesis of some a amido b hydroxy acids 2 On the synthesis of serine and cystine Annalen der Chemie in German 337 236 263 doi 10 1002 jlac 19043370205 Discussion of the synthesis of cystine begins on p 241 Erlenmeyer s findings regarding the structure of cystine were confirmed in 1908 by Fischer and Raske See Fischer Emil Raske Karl 1908 Verwandlung des l Serines in aktives naturliches Cystin Conversion of l serine into optically active natural cystine Berichte der Deutschen Chemischen Gesellschaft in German 41 893 897 doi 10 1002 cber 190804101169 Aslaksena M A Romarheima O H Storebakkena T Skrede A 28 June 2006 Evaluation of content and digestibility of disulfide bonds and free thiols in unextruded and extruded diets containing fish meal and soybean protein sources Animal Feed Science and Technology 128 3 4 320 330 doi 10 1016 j anifeedsci 2005 11 008 Gahl William A Thoene Jess G Schneider Jerry A 2002 Cystinosis New England Journal of Medicine 347 2 111 121 doi 10 1056 NEJMra020552 PMID 12110740 Frassetto L Kohlstadt I 2011 Treatment and prevention of kidney stones an update Am Fam Physician 84 11 1234 42 PMID 22150656 Cystine stones UpToDate Archived from the original on 26 February 2014 Retrieved 20 February 2014 External links edit nbsp Media related to Cystine at Wikimedia Commons Retrieved from https en wikipedia org w index php title Cystine amp oldid 1179796787, wikipedia, wiki, book, books, library,

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