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Purification and Characterization of a Tripeptidase from Lactobacillus sake
Sanz1, Mulholland, Toldrá
1Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Apartado 73, 46100 Burjassot (Valencia), Spain, and Institute of Food Research, Reading Laboratory, Earley Gate, Whiteknights Road, Reading RG6 2BZ, U.K.
Journal of Agricultural and Food Chemistry
|February 7, 2001
Summary
Researchers purified a novel tripeptidase from Lactobacillus sake, finding it optimal at pH 7.0 and 40°C. This enzyme specifically hydrolyzes tripeptides, with Mn(2+) activation and Zn(2+) inhibition.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Tripeptidases play crucial roles in protein metabolism and peptide absorption.
- Understanding the specific properties of microbial tripeptidases can offer insights into their physiological functions and potential applications.
Purpose of the Study:
- To purify and characterize a tripeptidase from Lactobacillus sake.
- To determine the enzyme's optimal conditions, molecular weight, and susceptibility to inhibitors and activators.
Main Methods:
- Purification involved ammonium sulfate precipitation, hydrophobic interaction chromatography, gel filtration, and anion exchange chromatography.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration were used for molecular mass estimation.
- Enzyme activity assays were performed under varying pH, temperature, and in the presence of different effectors.
Main Results:
- A homogeneous tripeptidase of approximately 55 kDa was isolated.
- Optimal activity was observed at pH 7.0 and 40°C.
- The enzyme was inhibited by metal chelators, reducing agents, and bestatin, activated by Mn(2+), and inhibited by Zn(2+).
- Specific tripeptides like Ala-Ala-Ala, Ser-Ser-Ser, and Leu-Gly-Gly were efficiently hydrolyzed.
Conclusions:
- Lactobacillus sake possesses a unique tripeptidase with specific biochemical properties.
- The enzyme's characteristics suggest a role in peptide metabolism within the bacterium.
- Further research could explore its potential in food processing or therapeutic applications.
