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Defining Substrate Specificities for Lipase and Phospholipase Candidates
Published on: November 23, 2016
Isolation and characterization of proteinase- and aminopeptidase-deficient mutants of Lactobacillus casei subsp.
P Fernández de Palencia1, M C Martín-Hernández, H M Joosten
1Instituto del Frío (CSIC), Ciudad Universitaria, Madrid, Spain.
Abstract:
Proteinase-deficient (Prt-) and aminopeptidase-deficient (Amp-) variants of Lactobacillus casei subsp. casei IFPL 731 were isolated and characterized. The Prt- mutant was isolated from strains that developed poorly on glucose milk agar. The Amp- mutant was isolated on the basis of its inability to hydrolyse L-leucine-beta-naphtylamide. The Prt- variant developed poorly, while in milk the Amp- variant grew at about the same rate as the parental strain. The characterization of aminopeptidase activity in more detail showed that at least two enzymes are involved The results of the present study suggest that the proteolytic system of Lactobacillus casei is subjected to a regulatory system.
Insights
Researchers isolated proteinase-deficient (Prt-) and aminopeptidase-deficient (Amp-) variants of Lactobacillus casei. The study suggests Lactobacillus casei
Area of Science:
- Microbiology
- Enzymology
- Lactic acid bacteria research
Background:
- Lactobacillus casei subsp. casei IFPL 731 is a significant bacterium.
- Understanding its proteolytic system is crucial for industrial applications.
- Deficiencies in proteinase and aminopeptidase can impact bacterial function.
Purpose of the Study:
- To isolate and characterize proteinase-deficient (Prt-) and aminopeptidase-deficient (Amp-) variants of Lactobacillus casei.
- To investigate the impact of these deficiencies on bacterial growth and activity.
- To elucidate the regulatory mechanisms of the Lactobacillus casei proteolytic system.
Main Methods:
- Isolation of Prt- and Amp- mutants from Lactobacillus casei.
- Growth assessment of mutant strains on glucose milk agar and in milk.
- Characterization of aminopeptidase activity using L-leucine-beta-naphtylamide hydrolysis.
- Detailed analysis of aminopeptidase enzymes involved.
Main Results:
- A Prt- mutant was isolated, showing poor development on glucose milk agar.
- An Amp- mutant was isolated based on its inability to hydrolyze L-leucine-beta-naphtylamide.
- The Prt- variant exhibited poor growth, while the Amp- variant grew similarly to the parental strain in milk.
- Characterization revealed the involvement of at least two enzymes in aminopeptidase activity.
Conclusions:
- The proteolytic system of Lactobacillus casei is regulated.
- Aminopeptidase activity involves multiple enzymatic components.
- Further research into Lactobacillus casei proteolytic regulation is warranted.
