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Appl. Environ. Microbiol., 04 1997, 1284-1287, Vol 63, No. 4
RO Tobiassen, T Sorhaug and L Stepaniak
An intracellular oligopeptidase from Lactobacillus paracasei Lc-01 has been
purified to homogeneity by Fast Flow Q Sepharose, hydroxyapatite, and Mono
Q chromatography. The molecular mass of the enzyme was determined to be 140
kDa by gel filtration and approximately 30 kDa by sodium dodecyl sulfate
(SDS)-polyacrylamide gel electrophoresis and SDS- capillary
electrophoresis. The pI of the enzyme was at pH 4.5. The enzyme expressed
maximum activity at pH 8.0 and 40 degrees C. Oligopeptidase activity on
bradykinin was inhibited strongly by 1,10- phenantroline and EDTA and
partly by p-chloromercuribenzoic acid but not by phosphoramidon or
phenylmethylsulfonyl fluoride. Marked inhibition by beta-casein fragment 58
to 72 was demonstrated. The enzyme showed neither general aminopeptidase
nor caseinolytic activity, and it degraded only oligopeptides between 8 and
13 amino acids. The enzyme 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. Weak
activity toward the Ala-Tyr and Pro-Ser bonds of alpha(s1)-casein fragment
157 to 164, was observed. The N-terminal amino acid sequence of the
oligopeptidase showed a high degree of homology to the lactacin B inducer
from Lactobacillus acidophilus.
Copyright © 1997, American Society for Microbiology
Characterization of an intracellular oligopeptidase from Lactobacillus paracasei
Department of Food Science, Agricultural University of Norway, As, Norway.
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