[Stabilization of Na+, K+-adenosine triphosphatase by dimethyl sulfoxide under inactivation by urea].

Hydrophobic agents, e.g. methanol, ethanol, isopropanol, acetone and dioxane were shown to induce irreversible inactivation of Na+, K+-adenosine triphosphatase beginning with their concentrations of 20 to 35%, whereas dimethyl sulphoxide exerted similar effect only at concentration of 50% and higher. Urea also irreversibly inactivated Na+, K+-adenosine triphosphatase, beginning with a concentration of about 20%. It was found that, dimethyl sulphoxide contrary to the other hydrophobic agents studied, protected Na+, K+-adenosine triphosphatase against the inactivating (denaturing) action of urea. The highest stabilizing effect of dimethyl sulphoxide was displayed at concentrations from 20 to 30%.