Oxidoreductases;
Acting on single donors with incorporation of molecular oxygen (oxygenases);
With incorporation of two atoms of oxygen
BRITE hierarchy

L-cysteine:oxygen oxidoreductase (2-oxoethane-1-sulfonamide-forming)

L-cysteine + 2 O2 = 2-oxoethane-1-sulfonamide + CO2 + H2O (overall reaction) [RN:R13404];
(1a) L-cysteine + O2 = (Z)-(2-aminovinyl)sulfanolate + CO2 + H2O [RN:R13405];
(1b) (Z)-(2-aminovinyl)sulfanolate + O2 = (Z)-2-aminoethene-1-sulfonate [RN:R13406];
(1c) (Z)-2-aminoethene-1-sulfonate + H2O = 2-oxoethane-1-sulfonamide + H2O [RN:R13407]

R13404 R13405 R13406 R13407
Reaction

L-cysteine [CPD:C00097];
O2 [CPD:C00007];
(Z)-(2-aminovinyl)sulfanolate [CPD:C22976];
(Z)-2-aminoethene-1-sulfonate [CPD:C22977];
H2O [CPD:C00001]

The enzyme, characterized from the bacterium Streptomyces sp. NCIMB40513, is a cupin dioxygenase that participates in the biosynthesis of the monoterpene alkaloids altemicidin, SB-203207 and SB-203208. The enzyme catalyses a complex transformation: it first catalyses a monooxygenation of the sulfur atom, which results in decarboxylation and formation of (Z)-(2-aminovinyl)sulfanolate. This is followed by a dioxygenation of the sulfur atom, forming (Z)-2-aminoethene-1-sulfonate. The resulting compound is unstable and undergoes an intramolecular rearrangement in which the amino group moves onto the oxidized sulfur atom, displacing an oxygen atom in the form of a water molecule and forming an SN bond. Another water molecule (not shown in the overall reaction) donates an oxygen atom that replaces the nitrogen at the other end of the molecule.

EC 1.13.11.95 created 2024

1  [PMID:30643149]