Immobilized soybean trypsin inhibitor
Soybean trypsin inhibitor (SBTI) is a reversible competitive inhibitor of trypsin and other trypsin-like proteases such as chymotrypsin, plasmin and plasma kallikrein. It has a MW of 22 kDa and a pI of 4.5 (1,2). We have immobilized SBTI on an agarose resin via coupling to primary amines to create an affinity resin with specificity for a number of serine proteases. SBTI binds free trypsin tighter with increasing pH from 4.5-8.0 that allows for a simple gradient to low pH (~2.5-3.0) for elution (1). References: 1. Birk, Y. (1976) Methods Enzymol. 55:700-706. 2. Kassell, B. (1970) Methods Enzymol. 19:853-862.