Kinetic studies of the phenol sulphotransferase reaction

Abstract

The kinetics of the reversible sulphotransferase-catalysed reaction between p-nitrophenol and 3′-phosphoadenylyl sulphate to give p-nitrophenyl sulphate and adenosine 3′,5′-diphosphate have been investigated using a partially purified sulphotransferase from guinea-pig liver. From a study of the initial velocities of the reactions in the forward and reverse directions at different substrate concentrations, and of the inhibitory effects of the products on the forward reaction, it was concluded that the mechanism was that of a rapid equilibrium random bi bi reaction upon which was superimposed the formation of a dead-end complex of the enzyme, p-nitrophenol and adenosine 3′,5′-diphosphate. Studies of the specificity of the enzyme have been made. Attempts to detect a transfer reaction between p-nitrophenyl sulphate and 2-naphthol with adenosine 3′,5′-diphosphate as a cofactor were unsuccessful.