Ovothiol A

Ovothiol A
Names
	Systematic IUPAC name (2S)-2-Amino-3-(1-methyl-4-sulfanyl-1H-imidazol-5-yl)propanoic acid
	Other names 1-N-Methyl-4-mercaptohistidine
Identifiers
CAS Number	108418-13-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:83318 ;
ChemSpider	115159;
MeSH	C061475
PubChem CID	130131;
UNII	BJK39KC2PD ;
CompTox Dashboard (EPA)	DTXSID90910720 ;
	InChI InChI=1S/C7H11N3O2S/c1-10-3-9-6(13)5(10)2-4(8)7(11)12/h3-4,13H,2,8H2,1H3,(H,11,12)/t4-/m0/s1 Key: XWKKYVJREGXHFO-BYPYZUCNSA-N; InChI=1/C7H11N3O2S/c1-10-3-9-6(13)5(10)2-4(8)7(11)12/h3-4,13H,2,8H2,1H3,(H,11,12)/t4-/m0/s1 Key: XWKKYVJREGXHFO-BYPYZUCNBB;
	SMILES CN1C=NC(=C1C[C@@H](C(=O)O)N)S;
Properties
Chemical formula	C7H11N3O2S
Molar mass	201.24 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Ovothiol A (N1-methyl-4-mercaptohistidine) is a highly reducing antioxidant mercaptohistidine, which accumulates to very high levels in the eggs of certain marine invertebrates, including sea urchins, scallops and starfish,^[1] where it acts to scavenge hydrogen peroxide released during fertilization.^[2]

This thiol is also found in some human pathogens including trypanosomes and members of the genus Leishmania.^[3]

It is synthesized by the addition and oxidation of cysteine to histidine by 5-histidylcysteine sulfoxide synthase, followed by methylation and further reduction.

References

^ Turner, E.; Klevit, R.; Hager, L. J. & Shapiro, B. M. (1987). "Ovothiols, a family of redox-active mercaptohistidine compounds from marine invertebrate eggs". Biochemistry. 26 (13): 4028–4036. doi:10.1021/bi00387a043. PMID 3651433.
^ Turner, E.; Hager, L. J. & Shapiro, B. M. (1988). "Ovothiol replaces glutathione-peroxidase as a hydrogen-peroxide scavenger in sea-urchin eggs". Science. 242 (4880): 939–941. Bibcode:1988Sci...242..939T. doi:10.1126/science.3187533. PMID 3187533. S2CID 5820883.
^ Spies, H.S. & Steenkamp, D.J. (1994). "Thiols of intracellular pathogens. Identification of ovothiol A in Leishmania donovani and structural analysis of a novel thiol from Mycobacterium bovis". Eur. J. Biochem. 224 (1): 203–213. doi:10.1111/j.1432-1033.1994.tb20013.x. PMID 8076641.