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Identification of an “alcohol dehydrogenase‐activating” protease in grass carp hepatopancreas as A chymotrypsin
Author(s) -
Lau Kingkwan,
Chan Elaine Yeeman,
Fong Wingping
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700205061
Subject(s) - hepatopancreas , grass carp , chymotrypsin , protease , alcohol dehydrogenase , biochemistry , chemistry , biology , alcohol , enzyme , fish <actinopterygii> , fishery , trypsin
Previous investigation [Tsui et al. (1996) Biochim. Biophys. Acta 1269: 41‐46] showed that two active forms of alcohol dehydrogenase can be purified from grass carp. The use of a protease inhibitor and the results of SDS‐PAGE analysis of the enzymes suggest that one form (ADH‐C) is a proteolytic product of the other (ADH‐I). In this study, the protease responsible for the cleavage was purified. The cleavage enzyme had a subunit molecular weight of 28 kDa. An inhibitor study identified it as a serine protease. It exhibited a strong chymotrypsin activity in both esterase and amidase assays with a pH optimum in the range 7.5‐8.5. The purified chymotrypsin also cleaved the intact grass carp ADH‐I into the two‐fragment ADH‐C, with an accompanying increase in enzyme activity. A similar effect was not found using horse liver alcohol dehydrogenase.