SYNTHESIS OF IMIDAZOLE-CONTAINING SILICAS BY CHEMICAL ASSEMBLY, AND STUDY OF THEIR CATALYTIC PROPERTIES.

The purpose of this investigation was to synthesize grafted imidazole groups on a modified Silochrome surface and to use this system as a heterogeneous catalyst for hydrolysis of p-nitrophenyl acetate (substrate for serine proteases). The experimental results show that the surface concentration of imidazole has a significant influence on the rate of catalytic hydrolysis of p-nitrophenyl acetate. At a certain concentration of imidazole on the surface (0. 054 mmole/g) the rate constant of the catalytic reaction increased by a factor of more than 3; this can probably be attributed to acceleration of the process because of the possibility of adsorption of the substrate on imidazole-free reactive groups on the surface. As a result of this, orientation of substrate molecules and of grafted functional groups more favorable for hydrolysis becomes possible. It can be concluded on the basis of this investigation that chemical assembly is a promising method for modeling processes occurring during enzyme catalysis.