The catalytic properties of a proteinase isolated from sheep abosamal mucosal mast cells

Abstract

1. 1. The catalytic properties of a sheep mast cell proteinase (SMCP), isolated from abomasal mucosal mast cells, were investigated. 2. 2. The enzyme was shown to have chymotrypsin-like esterase activity, with no detectable amide activity, using a range of low molecular weight substrates. 3. 3. Maximal activity, against Benzyloxycarbonyl- L-tyrosine-4-nitrophenol ester, was determined to be in the range pH 7.6–8.0. 4. 4. Inhibitor studies showed that, unlike chymotrypsin, a serine proteinase, SMCP was found to be susceptible to the action of thiol blocking agents and chilating agents, but to be unaffected by diisopropylphosphofluoridate, a serine proteinase inhibitor.