|
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 |
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