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Purification and Characterization of a Dipeptidase from Streptococcus cremoris Wg2
A van Boven1, P S T Tan, W N Konings
1Department of Microbiology, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
Applied and Environmental Microbiology
|January 1, 1988
Summary
Researchers purified a manganese-dependent dipeptidase from Streptococcus cremoris Wg2. This enzyme efficiently hydrolyzes dipeptides, offering insights into bacterial metabolism and enzyme function.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Dipeptidases play crucial roles in cellular protein metabolism.
- Streptococcus cremoris Wg2 is a significant lactic acid bacterium.
- Understanding microbial enzyme function is key to various biotechnological applications.
Purpose of the Study:
- To purify and characterize a novel dipeptidase from Streptococcus cremoris Wg2.
- To determine the enzyme's kinetic properties and optimal conditions.
- To elucidate the enzyme's cofactor requirements and inhibition patterns.
Main Methods:
- Purification using DEAE-Sephacel chromatography and preparative disc gel electrophoresis.
- Enzyme characterization via Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for molecular weight determination.
- Activity assays across various pH and temperature ranges, substrate specificity tests, and kinetic analyses (Km, Vmax).
Main Results:
- A homogeneous dipeptidase with a molecular weight of 49,000 Da was isolated.
- The enzyme demonstrated optimal activity at pH 8 and 50°C, functioning as a metallo-manganese enzyme.
- High catalytic rates (Vmax) were observed for leucyl-leucine and alanyl-alanine hydrolysis, despite relatively low affinities (Km).
Conclusions:
- The purified dipeptidase is a novel metalloenzyme critical for Streptococcus cremoris Wg2's metabolic processes.
- Its specific characteristics, including high turnover rates, suggest potential applications in food processing or biotechnology.
- Further research into its inhibition by thiol-reducing reagents warrants investigation.
