Specific protection by sulfhydryl groups against inhibition of urease by hypoglycaemic drugs

Abstract

The effect of oral hypoglycaemic drugs, derivatives of sulphonylurea, upon urease has been studied. These compounds, structurally connected to urea, produce a competitive inhibition of enzyme activity with respect to substrate. Glutathioné (reduced form) and cysteine prevent inactivation of enzyme by sulphonylurea, whereas-oxidated glutathione and cysteine do not. The same phenomenon occurs in enzyme preparations inhibited by p-hydroxymercuribenzoate. The role of sulfhydryl groups in the formation of enzyme-substrate complex is discussed.