Artículos de revistas
Modulation of the cell-surface proteinase activity of thermophilic lactobacilli by the peptide supply
Fecha
2002-12Registro en:
Hebert, Elvira Maria; Raya, Raul Ricardo; Savoy, Graciela; Modulation of the cell-surface proteinase activity of thermophilic lactobacilli by the peptide supply; Springer; Current Microbiology; 45; 6; 12-2002; 385-389
0343-8651
1432-0991
CONICET Digital
CONICET
Autor
Hebert, Elvira Maria
Raya, Raul Ricardo
Savoy, Graciela
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 α- and β-casein degradation, four types of PIII-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.