Purification from rat liver of an enzyme that catalyses the sulphurylation of phenols

Abstract

1. An enzyme (EC 2.8.2.1) that catalyses the transfer of sulphate from adenosine 3′-phosphate 5′-sulphatophosphate to phenols was purified approx. 2000-fold from male rat livers. 2. The purified preparation did not catalyse the sulphurylation of dehydroepiandrosterone, butan-1-ol, l-tyrosine methyl ester, 1-naphthylamine or serotonin. 3. At pH8.0 and 37°C the K_m values of the enzyme for p-nitrophenol and adenosine 3′-phosphate 5′-sulphatophosphate are 51 and 14μm respectively. The K_m value for either substrate is independent of the concentration of the other. 4. The sulphurylation of phenol is inhibited by thiol compounds and glutathione at a concentration of 3mm caused an approx. 50% decrease in enzyme activity. 5. The K_m of the enzyme for adenosine 3′-phosphate 5′-sulphatophosphate is unaffected by the presence of added glutathione but at a concentration of 5mm-glutathione the K_m of the enzyme for its phenolic substrate is decreased.