Influence of heat treatment in the presence of certain metal ions on the spectral-fluorescent properties of an amylolytic enzyme preparation. N.E. KULIKOVA, A.G. CHERNOBROVINA, N.N. ROEVA,Yu. POPOVA

Abstract

Influence of heat treatment in the presence of certain metal ions on the spectral-fluorescent properties of an amylolytic enzyme preparation. N.E. KULIKOVA, A.G. CHERNOBROVINA, N.N. ROEVA (Moscow State
University of Food Production, Moscow), O.Yu. POPOVA (International Technological College of Moscow State
University of Food Production, Moscow).

The heat treatment of enzyme preparations leads to a noticeable change in their activity as a result of certain conformational changes in the enzyme molecule. On mastering the study of ultraviolet spectra, the authors judge a change in the polarity of the environment of tryptophan residues with the addition of zinc, aluminum and calcium ions. The paper presents the results of studying the fluorescence spectra of an enzyme preparation: glucoamylase ultraconcentrate Asp. awamori after heat treatment and the addition of certain ions of some metals to detect structural changes in the enzyme molecule under these influences. It was found that the combined effect of metal ions and thermal effects on the aqueous solution of the enzyme preparation of glucoamylase ultraconcentrate Asp. awamori, leads to an increase in luminescence intensity and a shift of λ_max in the fluorescence spectra of Asp. awamori glucoamylase ultraconcentrate to the region of shorter wavelengths. This indicates an increase in the hydrophobicity of the tryptophan environment and provides confirmation of conformational changes in the enzyme molecule under the action of ions of certain metals and upon thermal exposure.