Some water‐insoluble papain derivatives

A description is given of the preparation and properties of four water‐insoluble papain derivatives by three different techniques: (a) covalent binding to a water‐insoluble diazoimitn salt derived from a copolymer of p‐aminophenylalanine and leucine; (b) binding to insoluble preparations of collagen via bisdiazobenzidine‐2,2′‐disulfonic acid; (c) in‐solubilization by crosslinking the enzyme itself with bisdiazobenzidine. By all three methods it, was possible to obtain stable water‐insoluble papain derivatives retaining much of the activity of the native enzyme on low and high molecular weight substrates.