M.G. Holyavka, V.G. Artyukhov, T.A. Kovaleva

It is shown that at incubation of inulinase with SDS in concentration of 3,510-3 and 3,510-4 mol/l probably there is inulinases denaturation. At SDS action in concentration of 3,510-6 mol/l the microenvironment of proteins chromophores is changed and the «hidden» radicals of aromatic amino acids can appear on a molecular surface; the quarternary structure of enzyme remains at this concentration of SDS. At SDS influence in concentration of 3,510-5 mol/l there are deeper reorganizations in a inulinase molecule: its dissociation on two asymmetric subunits. The molecular masses of subunits, calculated by results of our experiments, made 76,9 and 10,1 kDa. Further researches of inulinase and its separate subunits were carried out by means of the UR-spectroscopy method. Results showed that the quarternary structure of enzyme is stabilized, apparently, by mainly hydrophobic forces. For the purpose to identificate the role of dissociation process at enzymes molecule on subunits in manifestation of functional inulinases activity we defined catalytic activity of its subunits: it is shown that activity of enzyme in a dimeric form is lower, than total activity of its subunits, and, therefore, processes of association and dissociation of enzymes subunits take part in regulation of inulinases catalytic activity.