Cystine

Cystine
Identifiers
CAS Number	56-89-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:35492 ;
ChEMBL	ChEMBL366563 ;
ChemSpider	575 ;
ECHA InfoCard	100.000.270
IUPHAR/BPS	5413;
KEGG	C01420 ;
PubChem CID	67678;
UNII	48TCX9A1VT ;
CompTox Dashboard (EPA)	DTXSID2046418 ;
	InChI 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) Key: LEVWYRKDKASIDU-UHFFFAOYSA-N ; 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;
	SMILES C(C(C(=O)O)N)SSCC(C(=O)O)N;
Properties
Chemical formula	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). verify (what is ?) Infobox references

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.