On the mechanism of hydrolysis of hydantoins by d-hydantoinase from Vigna angularis: inhibition studies
Inhibition studies were performed with d-hydantoinase from Vigna angularis. These studies were based on the fact that 5,5-di-substituted hydantoins are not recognizable substrates for the enzyme. Rac-5-methyl-5-phenylhydantoin was shown to be an efficient competitive inhibitor of this d-hydantoinase...
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Published in | Journal of molecular catalysis. B, Enzymatic Vol. 21; no. 3; pp. 107 - 111 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
01.01.2003
Elsevier Science |
Subjects | |
Online Access | Get full text |
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Summary: | Inhibition studies were performed with
d-hydantoinase from
Vigna angularis. These studies were based on the fact that 5,5-di-substituted hydantoins are not recognizable substrates for the enzyme.
Rac-5-methyl-5-phenylhydantoin was shown to be an efficient competitive inhibitor of this
d-hydantoinase (
K
i=1.28
mM). (
R)-5-mono-substituted hydantoins were identified as the proper substrates of the enzyme. It is proposed that this reaction is constituted by a prior fast racemization step that provides the necessary and constant feeding of (
R)-5-mono-substituted isomer and a latter (
R)-specific enzymatic hydrolysis. The enzyme must present a hydrophobic environment in the pro-
R face and a basic residue in the pro-
S face. The feedstock configuration, its molecular volume and the presence of hydrogen in position 5 of the hydantoin are the main factors responsible for the substrate specificity showed by this enzyme. |
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ISSN: | 1381-1177 1873-3158 |
DOI: | 10.1016/S1381-1177(02)00084-X |