Inhibitors for trypsin and chymotrypsin in seeds of the broad bean (Vicia faba) (author's transl)

Abstract

Several inhibitors for trypsin and chymotrypsin were detected in seeds of Vicia faba by isoelectric focussing. Their isoelectric points are at pH 8.5 (main peak with shoulder), at pH 9.1 (minor peak with shoulder) and in the range of pH 9.1-6.4 (several minor peaks with significant lower activities). From the mixture of inhibitors obtained by affinity chromatography on carrier bound trypsin, three inhibitors were isolated by preparative electrophoresis in polyacrylamide gel. On electrophoresis these inhibitors behaved uniformly at pH 9.2 and at pH 4.0. Their molecular weights are about 6000 daltons. The amount of basic amino acids is high, while methionine and isoleucine are absent. Beside of trypsin and chymotrypsin some serine proteinases of microbiol origin are inhibited. The thermal stability is quite high. The Vicia inhibitors therefore differ significantly from the Phaseolus inhibitors in several properties.