Soybean Bowman-Birk inhibitor conjugates with clinical dextran. Synthesis and antiproteolytic activity

Conjugates of the classical soybean Bowman-Birk inhibitor (BBI) with clinic al dextran were synthesized. Clinical dextran was preliminarily oxidized wi th periodate to dialdehydedextran (DAD). The effect of the degree of oxidat ion of DAD on coupling of the inhibitor was evaluated. The binding of the p rotein was shown to increase with increasing degree of DAD oxidation (5, 10 , 20%). Total coupling of the inhibitor occurred when the degree of oxidati on of the dextran was 20%;. The BBI-DAD (20%) conjugate contained 13% prote in with BBI/DAD molar ratio 1 : 1. The conjugates retained the ability to i nhibit trypsin (K-1 = 0.2-0.3 nM) and alpha -chymotrypsin (k(1) = 15-30 nM) . Thus, the coupling of BBI with the polymeric carrier caused practically n o decrease in the antiproteolytic activity of the inhibitor.