Properties of the major carboxypeptidase in the larvae of the webbing clothes moth, Tineola bisselliella.
The larvae of the webbing clothes moth, Tineola bisselliella contain two carboxypeptidases (EC 3.4.12-) and one of these has been purified by preparative polyacrylamide gel electrophoresis. Its pH optimum for the hydrolysis of N-benzyloxycarbonyl-glycyl-leucine was pH 7.5-7.7 and its molecular weight as judged by gel filtration was 72 000. It is strongly inhibited by disopropylfluorophosphate, thiol reagents and some metal cations and also by 1:10 phenanthroline but not EDTA. Km and V values for the hydrolysis of 13 N-acyl dipeptides were determined. The enzyme has a strong preference for neutral aliphatic amino acid residues and does not hydrolyse C-terminal proline, arginine or lysine. It is a true carboxypeptidase, requiring an L-amino acid in the C-terminal position, with a free carboxyl group and hydrolysing peptide substrates consecutively from the C-terminal end. Dipeptides are cleaved much more slosly than tripeptides or N-acyl dipeptides.
Properties of the major carboxypeptidase in the larvae of the webbing clothes moth, Tineola bisselliella. The larvae of the webbing clothes moth, Tineola bisselliella contain two carboxypeptidases (EC 3.4.12-) and one of these has been purified by preparative polyacrylamide gel electrophoresis. Its pH optimum for the hydrolysis of N-benzyloxycarbonyl-glycyl-leucine was pH 7.5-7.7 and its molecular weight as judged by gel filtration was 72 000. It is strongly inhibited by disopropylfluorophosphate, thiol reagents and some metal cations and also by 1:10 phenanthroline but not EDTA. Km and V values for the hydrolysis of 13 N-acyl dipeptides were determined. The enzyme has a strong preference for neutral aliphatic amino acid residues and does not hydrolyse C-terminal proline, arginine or lysine. It is a true carboxypeptidase, requiring an L-amino acid in the C-terminal position, with a free carboxyl group and hydrolysing peptide substrates consecutively from the C-terminal end. Dipeptides are cleaved much more slosly than tripeptides or N-acyl dipeptides.