Affiliation:
1. Department of Microbiology, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
Abstract
A dipeptidase was purified to homogeneity from a crude cell extract of
Streptococcus cremoris
Wg2 by DEAE-Sephacel column chromatography followed by preparative disc gel electrophoresis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme showed a single protein band with a molecular weight of 49,000. The dipeptidase is capable of hydrolyzing a range of dipeptides, but not peptides with longer chains. The enzyme was shown to be a metallo-Mn
2+
enzyme with a pH optimum of 8 and a temperature optimum of 50�C. The enzyme is strongly inhibited by thiol-reducing reagents but not by sulfhydryl reagents. Kinetic studies indicated that the enzyme has a relatively low affinity for leucyl-leucine and alanyl-alanine (
K
m
, 1.6 and 7.9 mM, respectively) but can hydrolyze these substrates at very high rates (
V
max
, 3,700 and 13,000 μmol/min per mg of protein, respectively).
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Reference35 articles.
1. An electrophoretic study of peptidases in starter Streptococci and in cheddar cheese;Cliffe A. J.;J. Appl. Bacteriol.,1979
2. Discontinous polyacrylamide gel electrophoresis of cell wall proteinases from variants of Streptococcus lactis;Cliffe A. J.;J. Appl. Bacteriol.,1985
3. A medium for the cultivation of lactobacilli;De Man J. C.;J. Appl. Bacteriol.,1960
4. Isolation and general properties of two intracellular amino peptidases of Streptococcus diacetylactis;Desmazeaud M. J.;Milchwissenschaft,1979
5. Modified colorimetric ninhydrin methods for peptidase assay;Doi E.;Anal. Biochem.,1981
Cited by
94 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献