Reaction: L-serine = pyruvate + NH3 (overall reaction)
(1a) L-serine = 2-aminoprop-2-enoate + H2O
(1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous)
(1c) 2-iminopropanoate + H2O = pyruvate + NH3 (spontaneous)
Other name(s): serine deaminase; L-hydroxyaminoacid dehydratase; L-serine deaminase; L-serine dehydratase; L-serine hydro-lyase (deaminating)
Systematic name: L-serine ammonia-lyase (pyruvate-forming)
Comments: Most enzymes that catalyse this reaction are pyridoxal-phosphate-dependent, although some enzymes contain an iron-sulfur cluster instead . The reaction catalysed by both types of enzymes involves the initial elimination of water to form an enamine intermediate (hence the enzyme’s original classification as EC 126.96.36.199, L-serine dehydratase), followed by tautomerization to an imine form and hydrolysis of the C-N bond. The latter reaction, which can occur spontaneously, is also be catalysed by EC 188.8.131.52, 2-iminobutanoate/2-iminopropanoate deaminase. This reaction is also carried out by EC 184.108.40.206, threonine ammonia-lyase, from a number of sources.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9014-27-1
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