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Characteristics of an alkaline proteinase and exopeptidase from shrimp ( Penaeus indicus ) muscle
Author(s) -
DOKE S. N.,
NINJOOR V.
Publication year - 1987
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.1365-2621.1987.tb14044.x
Subject(s) - exopeptidase , biochemistry , enzyme , shrimp , biology , chemistry , casein , fishery
Activities of an alkaline proteinase and an exopeptidase were detected in the muscle of shrimp. Both enzymes could be extracted with unbuffered 0.5% KCI. The shrimp muscle alkaline proteinase, optimally active at pH 8.0 and 60°C, was partially purified and characterized. The heat stable enzyme had an apparent molecular weight of 250 KDa. Protein substrates such as casein, azocasein, azocoll and hemoglobin were hydrolyzed by the enzyme while it showed no action on bovine serum albumin and the synthetic substrates of proteinases. Active site directed inhibition experiments suggested that the enzyme was a metal‐dependent serine proteinase. The shrimp exopeptidase cleaving amino acid naphthylamides at pH 6.8 and 40°C exhibited the characteristics of an aminopeptidase because of its susceptibility to bestatin, puromycin and a metal chelator.