EC Explorer
[browse EC tree] - [search]
EC 4.4.1.25 Details
show Brenda entryEC number
4.4.1.25
Accepted name
L-cysteate sulfo-lyase
Reaction
L-cysteate + H2O = hydrogensulfite + pyruvate + NH3 (overall reaction);;(1a) L-cysteate = hydrogensulfite + 2-aminoprop-2-enoate;;(1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous);;(1c) 2-iminopropanoate + H2O = pyruvate + NH3 (spontaneous)
Other name(s)
L-cysteate sulfo-lyase (deaminating),
CuyA,
L-cysteate bisulfite-lyase (deaminating,
pyruvate-forming)
Systematic name
L-cysteate hydrogensulfite-lyase (deaminating; pyruvate-forming)
Comment
A pyridoxal-phosphate protein. The enzyme cleaves a carbon-sulfur bond, releasing hydrogensulfite and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. The latter reaction, which can occur spontaneously, can also be catalysed by EC 3.5.99.10, 2-iminobutanoate/2-iminopropanoate deaminase. D-Cysteine can also act as a substrate, but more slowly. It is converted into hydrogen sulfide, pyruvate, and ammonia. This inducible enzyme from the marine bacterium Silicibacter pomeroyi DSS-3 forms part of the cysteate-degradation pathway.
History
created 2006
back to topEC Tree
1 Oxidoreductases
1.1 Acting on the CH-OH group of donors
4.4.1.7 created 1972, deleted 1976 4.4.1.12 created 1976, deleted 2003 4.4.1.18 created 2000, deleted 2002
