Acylation of Bowman-Birk soybean proteinase inhibitor by unsaturated fattyacid derivatives

A procedure was developed for acylation of Bowman-Birk soybean proteinase i nhibitor (BBI) by N-hydroxysuc-cinimide esters of oleic, linoleic, and a-li nolenic acids in a dimethyl sulfoxide-dioxane-pyridine mixture. BBI derivat ives containing two acylated amino groups were prepared with high yield. Th e use of the reversible modifier citraconic anhydride in the first stage of synthesis permitted the synthesis of hydrophobized BBI derivatives retaini ng high antitrypsin and antichymotrypsin activities. It was found that the insertion of two long-chain moieties in the BBI molecule decreases its ther mostability.