REGULATION OF THE GM1-GALACTOSIDASE SUPRAMOLECULAR STRUCTURE AND CATALYTIC ACTIVITY INVITRO

Regulation of the supramolecular organization and the catalytic activity of G(M1)-galactosidase (EC 3.2.1.23) and neuraminidase (EC 3.2.1.18) from human kidney was studied in a system of hydrated reversed micelles of Aerosol OT in octane. It was shown that both the catalytic activity and the oligomeric structure of the G(M1)-galactosidase in reversed micelles depend on the [H2O]/[Aerosol OT] molar ratio (w(o)). G(M1)-galactosidase 64-67 kDa monomers, 260 kDa tetramers, and 660 kDa octamers were obtained in systems with w(o) = 0-20, 25-30 and 30-40, respectively. The association of G(M1)-galactosidase monomers into an octamer results in the cooperative increase in enzymatic activity. 'Protective protein', a component of the G(M1)-galactosidase-neuraminidase native complex, was found to improve this association significantly.