Aryl sulfotransferase IV (EC 2.8.2.1), purified to homogeneity from male rat liver, catalyzes the sulfation of a variety of substituted phenols, including catecholamines, tyrosine esters, and peptides containing NH2-terminal tyrosine residues. An investigation of the mechanism of the enzyme was carried out using 2-chloro-4-nitrophenol as a model substrate. Kinetic, inhibition, and binding studi...