Characterization of an intracellular oligopeptidase from Lactobacillus paracasei

Article Abstract:

An intracellular oligopeptidase from Lactobacillus paracasei Lc-01 was purified to homogeneity by Fast Flow Q Sepharose, hydroxyapatite and Mono Q chromatography. The molecular mass of the enzyme was 140 kDa when measured by gel filtration and about 30 kDa by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and SDS-capillary electrophoresis. The enzyme had neither general aminopeptidase nor caseinolytic activity, and it degraded only oligopeptides between 8 and 13 amino acids. It readily hydrolyzed the Phe-Ser and Pro-Phe bonds of bradykinin; the Phe-His bond of angiotensin I; the Pro-Gln, Gln-Phe, and Phe-Gly bonds of substance P; and the Pro-Tyr bond of neurotensin.

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Extracellular protease from the Antarctic yeast Candida humicola

Article Abstract:

A strain of Candida humicola isolated from Antarctica secretes a protease in the culture medium. The secretion process and the protease was characterized. Results showed that protease secretion is induced by the presence of proteins in the medium, while protease activity was low in the presence of either ammonium sulfate or amino acids. Characterization of theenzyme showed that it is an acidic protease with a molecular mass of 36 kDa. Itis inhibited by pepstatin, iodoacetamide and sodium dodecyl sulfate. Although it was isolated from Antarctica, the enyzme's optimum temperature is 37 degreescelsius.

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Purification and partial characterization of an elastolytic serine protease of Prevotella intermedia

Article Abstract:

Pus samples of adult periodontal lesions were screened for elastolytic strains of Prevotella intermedia, and the elastase was purified to homogeneity. A total of seven elastolytic strains were isolated from three of five patients, indicating that these strains occur frequently in periodontal lesions. Characterization of the enzyme showed that it is a serine protease with a molecular mass of 31-kDa. It is proposed that microbial elastase contributes to tissue damage of the gingiva in P. intermedia-infected areas.

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