Cysteine sulfinic acid

Cysteine sulfinic acid
Names
	IUPAC name 2-amino-3-sulfinopropanoic acid
Identifiers
CAS Number	1115-65-7 ; unspecified stereocentres: 2381-08-0;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:16345 ;
ChEMBL	ChEMBL1160508;
ChemSpider	1266065 ;
DrugBank	DB02153;
ECHA InfoCard	100.012.935
IUPHAR/BPS	5447;
KEGG	C00606;
MeSH	cysteine+sulfinic+acid
PubChem CID	1549098;
UNII	UZY4HYK4ZX ;
CompTox Dashboard (EPA)	DTXSID20862546 ;
	InChI InChI=1S/C3H7NO4S/c4-2(3(5)6)1-9(7)8/h2H,1,4H2,(H,5,6)(H,7,8)/t2-/m0/s1 Key: ADVPTQAUNPRNPO-REOHCLBHSA-N ; InChI=1/C3H7NO4S/c4-2(3(5)6)1-9(7)8/h2H,1,4H2,(H,5,6)(H,7,8)/t2-/m0/s1 Key: ADVPTQAUNPRNPO-REOHCLBHBM;
	SMILES O=C(O)[C@@H](N)CS(=O)O;
Properties
Chemical formula	C3H7NO4S
Molar mass	153.15698
	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

Cysteine sulfinic acid is the organic compound with the nominal formula HO₂SCH₂CH(NH₂)CO₂H . It is a rare example of an amino acid bearing a sulfinic acid functional group. It is a white solid that is soluble in water. Like most natural amino acids, it is chiral, only the L-enantiomer occurs in nature, and it exists as the zwitterion at neutral pH. It is an intermediate in cysteine metabolism. It is not a coded amino acid, but is produced post-translationally.^[1]

Cysteine is oxidized by cysteine dioxygenase to form cysteine sulfinic acid. Cysteine sulfinic acid, in turn, is decarboxylated by sulfinoalanine decarboxylase to form hypotaurine, which in turn is oxidized by hypotaurine dehydrogenase to yield taurine.^[2] Proteins containing this residue are found at the active site of some nitrile hydratases.^[3]

Peptides containing the cysteine sulfinic acid residue are substrates for cysteine sulfinic acid reductase.^[4]

References

^ Hayward, Laura; Baud, Matthias G. J. (2025). "Cysteine sulfinic acid and sulfinylated peptides". RSC Chemical Biology. 6 (7): 1019–1033. doi:10.1039/D5CB00040H. PMC 12093155. PMID 40406162.
^ Sumizu K (1962). "Oxidation of hypotaurine in rat liver". Biochim. Biophys. Acta. 63: 210–212. doi:10.1016/0006-3002(62)90357-8. PMID 13979247.
^ Isao Endo, Masaki Nojiri, b, Masanari Tsujimura, Masayoshi Nakasako, Shigehiro Nagashima, Masafumi Yohda, Masafumi Odaka "Focused Review: Fe-type nitrile hydratase"Journal of Inorganic Biochemistry 2001, Volume 83, Issue 4, February 2001, Pages 247–253. doi:10.1016/S0162-0134(00)00171-9
^ Akter, Salma; Fu, Ling; Jung, Youngeun; Conte, Mauro Lo; Lawson, J. Reed; Lowther, W. Todd; Sun, Rui; Liu, Keke; Yang, Jing; Carroll, Kate S. (2018). "Chemical proteomics reveals new targets of cysteine sulfinic acid reductase". Nature Chemical Biology. 14 (11): 995–1004. doi:10.1038/s41589-018-0116-2. PMC 6192846. PMID 30177848.

[1] Hayward, Laura; Baud, Matthias G. J. (2025). "Cysteine sulfinic acid and sulfinylated peptides". RSC Chemical Biology. 6 (7): 1019–1033. doi:10.1039/D5CB00040H. PMC 12093155. PMID 40406162.

[2] Sumizu K (1962). "Oxidation of hypotaurine in rat liver". Biochim. Biophys. Acta. 63: 210–212. doi:10.1016/0006-3002(62)90357-8. PMID 13979247.

[3] Isao Endo, Masaki Nojiri, b, Masanari Tsujimura, Masayoshi Nakasako, Shigehiro Nagashima, Masafumi Yohda, Masafumi Odaka "Focused Review: Fe-type nitrile hydratase"Journal of Inorganic Biochemistry 2001, Volume 83, Issue 4, February 2001, Pages 247–253. doi:10.1016/S0162-0134(00)00171-9

[4] Akter, Salma; Fu, Ling; Jung, Youngeun; Conte, Mauro Lo; Lawson, J. Reed; Lowther, W. Todd; Sun, Rui; Liu, Keke; Yang, Jing; Carroll, Kate S. (2018). "Chemical proteomics reveals new targets of cysteine sulfinic acid reductase". Nature Chemical Biology. 14 (11): 995–1004. doi:10.1038/s41589-018-0116-2. PMC 6192846. PMID 30177848.

[1]

[2]

[3]

[4]