CONJUGATION OF THE BOWMAN-BIRK SOYBEAN PROTEINASE-INHIBITOR WITH HYDROXYETHYLSTARCH

The classical Bowman-Birk soybean proteinase inhibitor was modified by hydroxyethylstarch. The modified inhibitor retained the capacity for simultaneous binding of trypsin and human leukocyte elastase. The inhi bition constants, K-i, of bovine trypsin, alpha-chymotrypsin and human leukocyte elastase (HLE) increased not more than 10-, 1.5-, and 20-fo ld, respectively, on modification of the inhibitor. The less effective inhibition is presumably due to the steric hindrance brought about by the conjugation with polysaccharide molecules. The results obtained i ndicate the pronounced structure differences of the binding regions fo r trypsin and chymotrypsin/leukocyte elastase in the modified preparat ion.