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Histidine and serine roles in catalytic activity of choline oxidase from Alcaligenes species studied by chemical modifications

Paper ID Volume ID Publish Year Pages File Format Full-Text
36185 45123 2006 6 PDF Available
Title
Histidine and serine roles in catalytic activity of choline oxidase from Alcaligenes species studied by chemical modifications
Abstract

This report concentrated on clarifying the histidine and serine roles in choline oxidase (ChOx) biocatalytic activity using chemical modifications. The serine and histidine residues on ChOx were chemically modified by diethylpyrocarbonate (DEPC) and phenylmethanesulfonyl fluoride (PMSF) at 100 mM Tris–HCl buffer, pH 8. The time course, inhibition kinetics and conformational changes of ChOx were investigated using spectrophotometric, fluorescence and Far-UV CD techniques. Enzyme activity decreased of 90% and 50% in the presence of DEPC and PMSF, respectively. The double reciprocal lineweaver-burk plots indicated a competitive and an uncompetitive inhibition pattern for DEPC and PMSF, respectively suggesting the location of histidine in the enzyme active site and that of serine in the outside of active site, but somewhere close to it.

Keywords
Choline oxidase; Histidine; Serine; Diethylpyrocarbonate; Chemical modification; Phenylmethanesulfonyl fluoride
First Page Preview
Histidine and serine roles in catalytic activity of choline oxidase from Alcaligenes species studied by chemical modifications
Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 41, Issue 2, February 2006, Pages 477–482
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering