The amino acid sequence of adzuki bean proteinase inhibitor I

Abstract

1. Introduction Proteins inhibiting the activity of proteinases are widely distributed in plant and animal tissues, and they are especially rich in leguminous seeds [ 11. Knowledge of the amino acid sequences of these proteinase inhibitors is important for studies on their structure- function relationships and molecular evolution. As for legume inhibitors, the amino acid sequences of Bowman-Birk soybean inhibitor [2] and two addi- tional soybean inhibitors [3] have been determined completely, and those of lima bean inhibitors IV and IV’ [4] and garden bean inhibitors II and II’ [S] nearly completely. These results show that these legume inhibitors are a family of low molecular weight proteins composed of about 70-80 amino acid residues and are double-headed, i.e., consisting of two domains each having a proteinase reactive site. Here, we report the amino acid sequence of adzuki bean proteinase inhibitor I, one of the major proteinase inhibitors isolated from adzuki bean (Phase&s