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Enhanced hydantoin-hydrolyzing enzyme activity in an Agrobacterium tumefaciens strain with two distinct N-carbamoylases

Paper ID Volume ID Publish Year Pages File Format Full-Text
17595 42682 2009 7 PDF Available
Title
Enhanced hydantoin-hydrolyzing enzyme activity in an Agrobacterium tumefaciens strain with two distinct N-carbamoylases
Abstract

Hydantoin-hydrolyzing enzymes of Agrobacterium tumefaciens isolates such as strain RU-OR are used as biocatalysts in the commercial production of d-hydroxyphenylglycine via hydrolysis of d, l-p-hydroxyphenylhydantoin. Hydantoin-hydrolyzing enzyme activity in RU-OR cells is tightly regulated by nitrogen catabolite repression and is induced when hydantoin or a hydantoin-analogue is present in the growth medium. Previous studies have selected mutant strains which are inducer-independent and no longer subject to nitrogen catabolite expression. However, these mutants did not exhibit significantly higher levels of enzyme activity compared to the wild-type strain. In this study, we have focused on enhancing the levels of hydantoinase and N-carbamoylase activity in wild-type RU-OR cells by manipulating the growth medium or over-expressing the global nitrogen regulatory factors, NtrBC. We also show that this strain encodes two distinct d-selective N-carbamoylases. One enzyme is virtually identical to the other Agrobacterium N-carbamoylases while the second represents a new class of d-N-carbamoylases with potentially novel biocatalytic properties.

Keywords
d-N-Carbamoylase; Enhanced hydantoin hydrolysis; Agrobacterium tumefaciens strain RU-OR
First Page Preview
Enhanced hydantoin-hydrolyzing enzyme activity in an Agrobacterium tumefaciens strain with two distinct N-carbamoylases
Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 44, Issue 4, 6 April 2009, Pages 203–209
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering