Browse history interactively

Page 1

Page 1Revision 1

Page 2

Page 2Revision 2

← Previous editContent deleted Content addedVisualWikitext

Revision as of 19:33, 7 August 2011 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Script assisted update of identifiers for the Chem/Drugbox validation project (updated: 'ChEBI').← Previous edit		Latest revision as of 19:22, 3 December 2024 edit undoFreaky.jpeg (talk | contribs)42 editsmNo edit summary
(126 intermediate revisions by 77 users not shown)
Line 1:		Line 1:
	{{distinguish|cysteine}}		{{distinguish|cytosine|cysteine|cytisine|cytidine}}
	{{chembox		{{chembox
			| Verifiedfields = changed
	| verifiedrevid = 414094421		| verifiedrevid = 443554604
	| ImageFileL1 = Cystine-skeletal.png		| ImageFileL1 = Cystine-from-xtal-2D-skeletal.png
	| ImageSizeL1 = 120px		| ImageSizeL1 = 150px
⚫	| ImageFileR1 = Cystine-3D-balls.png
			| ImageClassL1 = skin-invert-image
⚫	| ImageSizeR1 = 120px
		⚫	| ImageFileR1 = Cystine-from-xtal-Mercury-3D-balls-thin.png
		⚫	| ImageSizeR1 = 150px
	| IUPACName =		| IUPACName =
	| OtherNames =		| OtherNames =
	| Section1 = {{Chembox Identifiers		|Section1={{Chembox Identifiers
			| IUPHAR_ligand = 5413
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| ChemSpiderID = 575		| ChemSpiderID = 575
Line 25:		Line 28:
	| CASNo_Ref = {{cascite|correct|CAS}}		| CASNo_Ref = {{cascite|correct|CAS}}
	| CASNo = 56-89-3		| CASNo = 56-89-3
	| PubChem =		| PubChem = 67678
			| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 35492		| ChEBI = 35492
	| SMILES = C(C(C(=O)O)N)SSCC(C(=O)O)N		| SMILES = C(C(C(=O)O)N)SSCC(C(=O)O)N
	}}		}}
	| Section2 = {{Chembox Properties		|Section2={{Chembox Properties
	| C=6 | H=12 | N=2 | O=4 | S=2		| C=6 | H=12 | N=2 | O=4 | S=2
	| Appearance =		| Appearance =
Line 36:		Line 40:
	| BoilingPt =		| BoilingPt =
	| Solubility = }}		| Solubility = }}
	| Section3 = {{Chembox Hazards		|Section3={{Chembox Hazards
	| ExternalMSDS =		| ExternalSDS =
	| FlashPt =		| FlashPt =
	| Autoignition = }}		| AutoignitionPt = }}
	}}		}}
	'''Cystine''' is a ] ] formed by the oxidation of two ] residues that covalently link to make a ] bond. This ] has the ] (SCH<sub>2</sub>CH(NH<sub>2</sub>)CO<sub>2</sub>H)<sub>2</sub>. It is a white solid, and melts at 247-249 °C. It was discovered in 1810 by ] but was not recognized as being derived of ] until it was isolated from the ] of a ] in 1899.<ref>"cystine." Encyclopædia Britannica. 2007. Encyclopædia Britannica Online. 27 July 2007 </ref> Through formation of disulfide bonds within and between protein molecules, cystine is a significant determinant of the ] of most proteins. Disulfide bonding, along with hydrogen bonding and hydrophobic interactions is partially responsible for the formation of the gluten matrix in bread. Human hair contains approximately 5% cystine by mass.<ref>{{OrgSynth | author = Gortner, R. A.; W. F. Hoffman, W. F. | title = l-Cystine | collvol = 1 | collvolpages = 194 | year = 1941 | prep = CV1P0194}}</ref>		'''Cystine''' is the oxidized derivative of the ] ] and has the ] (SCH<sub>2</sub>CH(NH<sub>2</sub>)CO<sub>2</sub>H)<sub>2</sub>. It is a white solid that is poorly soluble in water. As a residue in proteins, cystine serves two functions: a site of ] reactions and a mechanical linkage that allows proteins to retain their ].<ref>Nelson, D. L.; Cox, M. M. (2000) ''Lehninger, Principles of Biochemistry''. 3rd Ed. Worth Publishing: New York. {{ISBN|1-57259-153-6}}.</ref>
	==Properties and nutritional aspects==		==Formation and reactions==
			===Structure===
	The disulfide link is readily reduced to give the corresponding thiol cysteine. This reaction is typically effected with thiols such as ] or ].
			Cystine is the ] derived from the amino acid ]. The conversion can be viewed as an oxidation:
⚫	:(SCH<sub>2</sub>CH(NH<sub>2</sub>)CO<sub>2</sub>H)<sub>2</sub> + 2 ] → 2 HSCH<sub>2</sub>CH(NH<sub>2</sub>)CO<sub>2</sub>H + RSSR
			:{{chem2|2 HO2CCH(NH2)CH2SH + 0.5 O2 -> (HO2CCH(NH2)CH2S)2 + H2O}}
⚫	For this reason, the nutritional benefits and sources of cystine are identical to those for the more-common cysteine. Disulfide bonds cleave more rapidly at higher temperatures.<ref>{{cite journal
			Cystine contains a ], 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 ]. The great majority of the literature concerns the ''l,l-''cystine, derived from ''l''-cysteine. Other isomers include ''d,d''-cystine and the ] d,l-cystine, neither of which is biologically significant.
	| author = M.A. Aslaksena, O.H. Romarheima, T. Storebakkena and A. Skrede
⚫	| title = Evaluation of content and digestibility of disulfide bonds and free thiols in unextruded and extruded diets containing fish meal and soybean protein sources
			=== Occurrence ===
⚫	| journal = Animal Feed Science and Technology
			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 ] until it was isolated from the ] of a ] in 1899.<ref>. ''Encyclopædia Britannica''. 2007. Encyclopædia Britannica Online. 27 July 2007</ref> Human hair and skin contain approximately 10–14% cystine by mass.<ref>{{OrgSynth | last1 = Gortner|first1=R. A.|first2=W. F.|last2=Hoffman | title = l-Cystine | volume= 5 | page= 39| year = 1925| prep = 10.15227/orgsyn.005.0039}}</ref>
⚫	| volume = 128
⚫	| issue = 3–4
			=== History ===
⚫	| pages = 320–330
⚫	| date = 28 June 2006
			Cystine was discovered in 1810 by the English chemist ], who called it "cystic oxide".<ref>{{cite journal |last1=Wollaston |first1=William Hyde |title=On cystic oxide, a new species of urinary calculus |journal=Philosophical Transactions of the Royal Society of London |date=1810 |volume=100 |pages=223–230 |url=https://www.biodiversitylibrary.org/item/213300#page/293/mode/1up}} On p. 227, Wollaston named cystine "cystic oxide".</ref><ref name=":0">{{Citation |last=Bradford Vickery |first=Hubert |title=The History of the Discovery of the Amino Acids II. A Review of Amino Acids Described Since 1931 as Components of Native Proteins |date=1972-01-01 |work=Advances in Protein Chemistry |volume=26 |pages=81–171 |editor-last=Anfinsen |editor-first=C. B. |url=https://www.sciencedirect.com/science/article/pii/S0065323308601400 |access-date=2024-05-13 |publisher=Academic Press |doi=10.1016/s0065-3233(08)60140-0 |editor2-last=Edsall |editor2-first=John T. |editor3-last=Richards |editor3-first=Frederic M.}}</ref> In 1833, the Swedish chemist ] named the amino acid "cystine".<ref>{{cite book |last1=Berzelius |first1=J.J. |last2=Esslinger |first2=Me., trans. |title=Traité de Chimie |date=1833 |publisher=Didot Frères |location=Paris, France |volume=7 |page=424 |url=https://books.google.com/books?id=7kkE6Ol3a8kC&pg=PA424 |language=French}} 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 alleged to justify it is not valid: I have therefore taken the liberty of changing the name that this distinguished man had proposed.)</ref> The Norwegian chemist ] determined, in 1838, the ] of cystine.<ref>{{cite journal |last1=Thaulow |first1=C. J. |title=Sur la composition de la cystine |journal=Journal de Pharmacie |date=1838 |volume=24 |pages=629–632 |url=https://books.google.com/books?id=LMc0AQAAMAAJ&pg=PA629 |trans-title=On the composition of cystine |language=French}}</ref> In 1884, the German chemist ] found that when cystine was treated with a reducing agent, cystine revealed itself to be a ] of a ] which he named ].<ref>{{cite journal |last1=Baumann |first1=E. |title=Ueber Cystin und Cysteïn |journal=Zeitschrift für physiologische Chemie |date=1884 |volume=8 |pages=299–305 |url=https://babel.hathitrust.org/cgi/pt?id=coo.31924078260563&view=1up&seq=309 |trans-title=On cystine and cysteine |language=German}} From pp. 301-302: ''"Die Analyse der Substanz ergibt Werthe, welche den vom Cystin (C<sub>6</sub>H<sub>12</sub>N<sub>2</sub>S<sub>2</sub>O<sub>4</sub>) verlangten sich nähern, nenne ich dieses Reduktionsprodukt des Cystins: Cysteïn."'' (Analysis of the substance reveals values which approximate those required by cystine (C<sub>6</sub>H<sub>12</sub>N<sub>2</sub>S<sub>2</sub>O<sub>4</sub>), however the new base can clearly be recognized as a reduction product of cystine, to which the formula C<sub>3</sub>H<sub>7</sub>NSO<sub>2</sub>, previously ascribed to cystine, is 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 CH<sub>3</sub>CNH<sub>2</sub>(SH)COOH .</ref><ref name=":0" /> In 1899, cystine was first isolated from protein (horn tissue) by the Swedish chemist Karl A. H. Mörner (1855-1917).<ref>{{cite journal |last1=Mörner |first1=K. A. H. |title=Cystin, ein Spaltungsprodukt der Hornsubstanz |journal=Hoppe-Seyler's Zeitschrift für Physiologische Chemie |date=1899 |volume=28 |issue=5–6 |pages=595–615 |doi=10.1515/bchm2.1899.28.5-6.595 |url=https://babel.hathitrust.org/cgi/pt?id=umn.31951002681071f&view=1up&seq=607 |trans-title=Cystine, a cleavage product of horn tissue |language=German}}</ref> The chemical structure of cystine was determined by synthesis in 1903 by the German chemist ].<ref>{{cite journal |last1=Erlenmeyer |first1=Emil |title=Synthese des Cystins |journal=Berichte der Deutschen Chemischen Gesellschaft |date=1903 |volume=36 |issue=3 |pages=2720–2722 |doi=10.1002/cber.19030360320 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.cl1i2b&view=1up&seq=72 |trans-title=Synthesis of cystine |language=German}}</ref><ref>{{cite journal |last1=Erlenmeyer |first1=E. jun. |last2=Stoop |first2=F. |title=Ueber die Synthese einiger α-Amido-β-hydroxysäuren. 2. Ueber die Synthese der Serins und Cystins |journal=Annalen der Chemie |date=1904 |volume=337 |pages=236–263 |doi=10.1002/jlac.19043370205 |url=https://babel.hathitrust.org/cgi/pt?id=pst.000067448074&view=1up&seq=246 |trans-title=On the synthesis of some α-amido-β-hydroxy acids. 2. On the synthesis of serine and cystine. |language=German}} Discussion of the synthesis of cystine begins on p. 241.</ref><ref>Erlenmeyer's findings regarding the structure of cystine were confirmed in 1908 by Fischer and Raske. See: {{cite journal |last1=Fischer |first1=Emil |last2=Raske |first2=Karl |title=Verwandlung des ''l''-Serines in aktives natürliches Cystin |journal=Berichte der Deutschen Chemischen Gesellschaft |date=1908 |volume=41 |pages=893–897 |doi=10.1002/cber.190804101169 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.cl1i2u&view=1up&seq=905 |trans-title=Conversion of ''l''-serine into active natural cystine |language=German}}</ref>
⚫	| doi = 10.1016/j.anifeedsci.2005.11.008 }}</ref>
			The history of cystine and ] is complicated by the dimer-monomer relationship of the two.<ref name=":0" /> The cysteine monomer was proposed as the actual unit by Embden in 1901.
			The sulfur within the structure of cysteine and cystine has been subject of historical interest.<ref name=":0" /> In 1902, Osborne partially succeeded in analysing cystine content via lead compounds. An improved colorimetric method was developed in 1922 by Folin and Looney. An iodometric analysis method was developed by Okuda in 1925.
			===Redox===
			It is formed from the oxidation of two cysteine molecules, which results in the formation of a ]. In cell biology, cystine residues (found in proteins) only exist in non-reductive (oxidative) organelles, such as the secretory pathway (], ], ]s, and vesicles) and extracellular spaces (e.g., ]). Under reductive conditions (in the cytoplasm, nucleus, etc.) cysteine is predominant. The disulfide link is readily reduced to give the corresponding ] ]. Typical thiols for this reaction are ] and ]:
		⚫	:(SCH<sub>2</sub>CH(NH<sub>2</sub>)CO<sub>2</sub>H)<sub>2</sub> + 2 RSH → 2 HSCH<sub>2</sub>CH(NH<sub>2</sub>)CO<sub>2</sub>H + 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 ]. Disulfide bonds cleave more rapidly at higher temperatures.<ref>{{cite journal
		⚫	|author1=Aslaksena, M.A. |author2=Romarheima, O.H. |author3=Storebakkena, T. |author4=Skrede, A. | title = Evaluation of content and digestibility of disulfide bonds and free thiols in unextruded and extruded diets containing fish meal and soybean protein sources
		⚫	| journal = Animal Feed Science and Technology
		⚫	| volume = 128
		⚫	| issue = 3–4
		⚫	| pages = 320–330
		⚫	| date = 28 June 2006
		⚫	| doi = 10.1016/j.anifeedsci.2005.11.008 }}</ref>
			===Cystine-based disorders===
			]
			The presence of cystine in urine is often indicative of amino acid reabsorption defects. ] has been reported to occur in dogs.<ref>{{cite journal|last1=Gahl|first1=William A.|last2=Thoene|first2=Jess G.|last3=Schneider|first3=Jerry A.|title=Cystinosis|journal=New England Journal of Medicine|volume=347|issue=2|year=2002|pages=111–121|doi=10.1056/NEJMra020552|pmid= 12110740}}</ref>
			In humans the excretion of high levels of cystine crystals can be indicative of ], a rare genetic disease. Cystine stones account for about 1-2% of ] in adults.<ref name=Frassetto2011>{{cite journal| author=Frassetto L, Kohlstadt I| title=Treatment and prevention of kidney stones: an update. | journal=Am Fam Physician | year= 2011 | volume= 84 | issue= 11 | pages= 1234–42 | pmid=22150656 | doi= | pmc= | url=https://pubmed.ncbi.nlm.nih.gov/22150656 }}</ref><ref>{{cite web|title=Cystine stones|url=http://www.uptodate.com/contents/cystine-stones|work=]|access-date=20 February 2014|url-status=live|archive-url=https://web.archive.org/web/20140226110022/http://www.uptodate.com/contents/cystine-stones|archive-date=26 February 2014|df=dmy-all}}</ref>
			==Biological transport==
			Cystine serves as a substrate for the ]. 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|date=October 2013}} Cysteine prodrugs, e.g. ], induce release of glutamate into the extracellular space.
			==Nutritional supplements==
			{{missing information|date=November 2022|reason='''hair growth supplements'''}}
			Cysteine supplements are sometimes marketed as anti-aging products with claims of improved skin elasticity.{{Citation needed|date=May 2020}} 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==		==See also==
		⚫	* ], similar with ''mono''-sulfide link
	* ]
			* ]
			* ]
	* ]		* ]
	* ]
⚫	* ], similar with ''mono''-sulphide link
	== References ==		==References==
	<references />		<references />
			==External links==
			*{{Commons category-inline}}
	{{E number infobox 920-929}}		{{E number infobox 920-929}}
			]
	]		]
	]		]
			]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]