Phenol sulfotransferases

Abstract

Two phenol sulfotransferases have been purified from rat liver by conventional techniques coupled with affinity chromatography on Affi-Gel blue and ATP-agarose. Both enzymes are homogeneous by the criterion of sodium dodecyl sulfate gel electrophoresis. Each enzyme has a molecular weight of approximately 65,000 and consists of two subunits of apparently equal size. The enzymes are also similar in specificity and in their kinetic parameters but differ in amino acid composition and in their elution from DEAE-cellulose. With adenosine 3'-phosphate 5'-phosphosulfate as donor, a large variety of phenolic compounds serve as sulfate acceptor; sterols, simple alcohols, bile acids, and hydroxamates do not serve as substrates. The transferases may be considered as detoxification enzymes which catalyze the conjugation of xenobiotics containing a phenol group or of phenolic compounds generated by endogenous oxidation. The enzymes act on 3-hydroxyindole to yield indican, suggesting that their in vivo function may include the production of this normal tryptophan metabolite.