INVESTIGADORES
RAYA Raul Ricardo
artículos
Título:
Modulation of the cell-surface proteinase activity of thermophilic lactobacilli by the Peptide supply.
Autor/es:
HÉBERT EM, RAYA RR, DE GIORI GS.
Revista:
CURRENT MICROBIOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: New York, NY 10013; Año: 2002 vol. 45 p. 385 - 389
ISSN:
0343-8651
Resumen:
The proteolytic system of thermophilic lactobacilli is considered
important for bacterial nutrition as well as for the formation of flavor
and texture in fermented products. We investigated the influence of
peptide content on the cell surface proteinase and intracellular
aminopeptidase activities from seven thermophilic lactobacilli strains.
The proteinase activities were remarkably reduced in cells grown in the
peptide-rich medium MRS or in a chemically defined medium supplemented
with Casitone compared with those found in a synthetic medium. The
degree of inhibition observed was strain dependent. When proteinase
activities were analyzed by their hydrolytic patterns of alpha- and
beta-casein degradation, four types of P(III)-caseinolytic cleavage
specificity were distinguished. Lactobacillus helveticus strains
possessed aminopeptidase activities with broader specificity than those
found in L. delbrueckii subsp. lactis strains. However, the
aminopeptidase activities were not influenced by the peptide content of
the medium.