Biopolymers and cell. 1996; 12 (3): 27 - 33

A proteolytic biosensor based on a pH-sensitive field effect transistor. 1. The comparative investigation of native and immobilized trypsin

O. A. Beloivan, A. P. Soldatkin, N. F. Starodub, A. V. El`skaya

The immobilization of trypsin on semiconductor surface was been made by cross Unking with bovin serum albumin in saturated glutaraldegyde ( GA ) vapours. The optimal conditions of this process were as follow¬ing: the ratio oftrypsin:BSA — 1:4, and incubation time in GA vapours — 2 hat room temperature. The influence of different concentrations of sucrose and glycerol on membrane characteristics has also been investigated. Addition of 2,0—2,5 % of glycerol increase membrane activity and its adhesion level to the surface. The catalytical characteristics of free and immobilized trypsin have been compared such as KM, dependence of the enzyme activity on pH, buffer capacity, ionic strength of analysing solution. The pos¬sibility to use trypsin membrane as sensitive element of proteolytic, biosensor has been discussed.