The Reactive Site Amino Acid Sequences of Silktree (Albizzia julibrissin) Seed Proteinase Inhibitors

Abstract

Two silktree (Albizzia julibrissin) seed proteinase inhibitors, A-II and B-II, which are homologs with soybean trypsin inhibitor (Kunitz), were cleaved with cyanogen bromide. Sequence analyses of the resulting fragments and comparison with the soybean inhibitor revealed the amino acid sequences around the reactive sites of both inhibitors. The primary reactive site of trypsin-chymotrypsin inhibitor A-II was identified as Arg66-Ile67 and that for chymotrypsin-elastase inhibitor B-II as Leu62-Met63. These results are the first reports of the reactive site sequences of homologous of soybean trypsin inhibitor (Kunitz).