Cysteine sulfinic acid

Cysteine sulfinic acid is the organic compound with the nominal formula HO2SCH2CH(NH2)CO2H .

It is not a coded amino acid, but is produced post-translationally.

Peptides containing the cysteine sulfinic acid residue are substrates for cysteine sulfinic acid reductase.

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.

Skeletal formula
Skeletal formula
Ball-and-stick model
Ball-and-stick model
Cysteine sulfinic acid (2) is an intermediate in the conversion of cysteine (1) to taurine (4).