Reaction: L-canavanine + H2O = L-homoserine + N-hydroxyguanidine (overall reaction)
(1a) L-canavanine = vinylglycine + N-hydroxyguanidine
(1b) vinylglycine = (2E)-2-aminobut-2-enoate (spontaneous)
(1c) (2E)-2-aminobut-2-enoate + H2O = L-homoserine (spontaneous)
Other name(s): CangL
Systematic name: L-canavanine N-hydroxyguanidine-lyase (L-homoserine-forming)
Comments: A pyridoxal-phosphate protein. The enzyme, characterized from the bacterium Pseudomonas canavaninivorans, cleaves a carbon-oxygen bond, releasing N-hydroxyguanidine and an unstable enamine product that tautomerizes to an imine form, which is attacked by a water molecule to form L-homoserine.
References:
1. Hauth, F., Buck, H., Stanoppi, M., and Hartig, J. S. Canavanine utilization via homoserine and hydroxyguanidine by a PLP-dependent γ-lyase in Pseudomonadaceae and Rhizobiales. RSC Chemical Biology (0) .