Dissociative thermal inactivation of beta-galactosidase and the structure of the conformational lock

It was established that, in adsorption layers of beta -galactosidase on mac roporous hydrothermal silica gel, the tetramer and dimer forms of the enzym e are more stable than in solutions. The presence of polysaccharides in the adsorption layers increases the stability of these oligomers. The kinetic parameters that characterize the thermal stability of beta -galactosidase w ere determined: the effective rate constants of inactivation, energy of act ivation, and the number of intermediate stages of the process without a los s of activity. On the basis of data of kinetic studies and X-ray diffractio n analysis, the structure of the conformational lock stabilizing the active sites in the dimers and tetramers of beta -galactosidase was suggested.