type	Journal Article
authors	Bild, G. S.; Morris, J. C.
title	Detection of beta-carbanion formation during kynurenine hydrolysis catalyzed by Pseudomonas marginalis kynureninase
journal	Arch Biochem Biophys
Activity	3.7.1.3
ui	85045537
year	(1984)
volume	235
number	1
pages	41-7.
keywords	Benzaldehydes/metabolism
abstract	2-Amino-4-hydroxy-4-phenylbutyric acid has been shown to be formed during the Pseudomonas marginalis kynureninase-catalyzed hydrolysis of kynurenine in the presence of benzaldehyde and pyridoxal phosphate. The formation of 2-amino-4-hydroxy-4-phenylbutyric acid is the first demonstration, to our knowledge, of the controlled trapping of an amino acid beta-carbanion generated either chemically or enzymatically, and is perhaps the best empirical evidence to date that enzyme mechanisms can proceed through a beta-carbanionic intermediate. The lifetime of the beta-carbanionic alanyl intermediate generated by kynureninase is of sufficient duration to allow reaction with benzaldehyde. Other aromatic, but no aliphatic, aldehydes will undergo electrophilic addition with kynureninase-generated beta-carbanionic alanyl intermediates to form the corresponding amino acid.
last changed	2002/11/12 16:17