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Purification and Characterization of Cathepsin B from the Skeletal Muscle of Fresh Water Fish, Tilapia mossambica
Author(s) -
SHEREKAR S.V.,
GORE M. S.,
NINJOOR V.
Publication year - 1988
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1988.tb13521.x
Subject(s) - tilapia , cathepsin b , biochemistry , chemistry , antipain , enzyme , cathepsin , hydrolysis , cathepsin l , aminopeptidase , endopeptidase , size exclusion chromatography , chromatography , microbiology and biotechnology , biology , fish <actinopterygii> , leucine , leupeptin , amino acid , protease , fishery
Cathepsin B from the skeletal muscle of a fresh water fish Tilapia mossambica was purified 4280‐fold with 9% recovery. The electrophoretic homogeneity of the preparation was established both under native and denatured conditions. The molecular weight of cathepsin B on the basis of its gel filtration profile was 23,500 daltons. The enzyme, an endopeptidase, hydrolysed Z‐arg‐arg‐NNap and Bz‐arg‐NNap, with Km values of 0.57 and 3.23 mM, respectively. Cathepsin B did not display aminopeptidase activity, but cleaved Bz‐arg‐NH 2 , exhibiting the specificity of a carboxypeptidase. Among protein substrates tested, only azocoll was hydrolyzed at lower pH values. Leu‐peptin, antipain and thiol blockers abolished the enzyme activity completely. The Kcat set ‐1 value of fish cathepsin B seemed to be lower than that of mammalian enzyme.