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Peptidase activity in various species of dairy thermophilic lactobacilli

Peptidase activity in various species of dairy thermophilic lactobacilli Aims: The aim of the present work was to evaluate the enzymatic potential manifested by aminopeptidase activity of different thermophilic Lactobacillus biotypes and to measure the influence of cell growth phase on enzyme expression. Methods and Results: The activities were evaluated by the hydrolysis of β‐naphthylamide substrates for both whole and mechanically disrupted cells of L. helveticus, L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis strains, collected from both the exponential and the stationary growth phase. In general, activities were higher for cells in the exponential rather than in the stationary phase and the disrupted cells showed higher activities than the whole cells. The highest activity expressed by all strains corresponded to X‐prolyl‐dipeptidyl aminopeptidase while a moderate activity was observed towards Arg‐βNa, Lys‐βNa and Leu‐βNa. The lowest activity was observed for Pro‐βNa. Conclusions: It may be inferred that the cell structure and the cell physiology are crucial to define the level of efficiency of expression for aminopeptidase activity. The two species may be characterized by a different enzymatic system that hydrolyses N‐terminal leucine. Significance and Impact of the Study: The differences of peptidase activities in L. helveticus and L. delbrueckii species acquires an importance to comprehend their role in the biochemical events occurring in cheese ripening. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Applied Microbiology Wiley

Peptidase activity in various species of dairy thermophilic lactobacilli

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References (22)

Publisher
Wiley
Copyright
Copyright © 2004 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1364-5072
eISSN
1365-2672
DOI
10.1046/j.1365-2672.2003.02142.x
Publisher site
See Article on Publisher Site

Abstract

Aims: The aim of the present work was to evaluate the enzymatic potential manifested by aminopeptidase activity of different thermophilic Lactobacillus biotypes and to measure the influence of cell growth phase on enzyme expression. Methods and Results: The activities were evaluated by the hydrolysis of β‐naphthylamide substrates for both whole and mechanically disrupted cells of L. helveticus, L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis strains, collected from both the exponential and the stationary growth phase. In general, activities were higher for cells in the exponential rather than in the stationary phase and the disrupted cells showed higher activities than the whole cells. The highest activity expressed by all strains corresponded to X‐prolyl‐dipeptidyl aminopeptidase while a moderate activity was observed towards Arg‐βNa, Lys‐βNa and Leu‐βNa. The lowest activity was observed for Pro‐βNa. Conclusions: It may be inferred that the cell structure and the cell physiology are crucial to define the level of efficiency of expression for aminopeptidase activity. The two species may be characterized by a different enzymatic system that hydrolyses N‐terminal leucine. Significance and Impact of the Study: The differences of peptidase activities in L. helveticus and L. delbrueckii species acquires an importance to comprehend their role in the biochemical events occurring in cheese ripening.

Journal

Journal of Applied Microbiology – Wiley

Published: Feb 1, 2004

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