IntEnz

EC 4.3.1.18 - D-serine ammonia-lyase

IntEnz Enzyme Nomenclature
EC 4.3.1.18

Names

Reactions

• (1) D-serine = pyruvate + NH3
•   (1a) D-serine = 2-aminoprop-2-enoate + H2O
•   (1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous)
•   (1c) 2-iminopropanoate + H2O = pyruvate + NH3 (spontaneous)

Cofactor

• pyridoxal 5'-phosphate

Comments:

A pyridoxal-phosphate protein. The enzyme cleaves a carbon-oxygen bond, releasing a water molecule (hence the enzyme's original classification as EC 4.2.1.14, D-serine dehydratase) 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. Also acts, slowly, on D-threonine.

Links to other databases

References

1. Dupourque, D., Newton, W.A. and Snell, E.E.
   Purification and properties of D-serine dehydrase from Escherichia coli.
   J. Biol. Chem. 241 : 1233-1238 (1966). [PMID: 5327100]
2. Metzler, D.E. and Snell, E.E.
   Deamination of serine. II. D-Serine dehydrase, a vitamin B₆ enzyme from Escherichia coli.
   J. Biol. Chem. 198 : 363-373 (1952). [PMID: 12999751]

[EC 4.3.1.18 created 1961 as EC 4.2.1.14, transfered 2001 to EC 4.3.1.18]