EC - β-(isoxazolin-5-on-2-yl)-L-alanine synthase

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IntEnz Enzyme Nomenclature


Accepted name:
β-(isoxazolin-5-on-2-yl)-L-alanine synthase
Systematic name:
O3-acetyl-L-serine:isoxazolin-5-one 2-(2-amino-2-carboxyethyl)transferase



The enzyme from the plants Lathyrus odoratus (sweet pea) and L. sativus (grass pea) also forms 3-(5-oxoisoxazolin-4-yl)-L-alanine in vitro (cf. EC However, only 3-(5-oxoisoxazolin-2-yl)-L-alanine is formed in vivo. 3-(5-oxoisoxazolin-2-yl)-L-alanine is the biosynthetic precursor of the neurotoxin N3-oxalyl-L-2,3-diaminopropanoic acid, the cause of lathyrism. Closely related and possibly identical to EC, cysteine synthase, and EC, β-pyrazolylalanine synthase.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Ikegami, F., Kamiya, M., Kuo, Y. H., Lambein, F., Murakoshi, I.
    Enzymatic synthesis of two isoxazolylalanine isomers by cysteine synthases in Lathyrus species.
    Biol. Pharm. Bull. 19: 1214-1215 (1996). [PMID: 8889043]

[EC created 2014]