Regulation of Arksulfate Sulfotransferase from a Human Intestinal Bacterium by Nucleotides and Magnesium Ion

Abstract

Arylsulfate sulfotransferase (ASST) from a human intestinal bacterium stoichiometrically catalyzed the transfer of a sulfate group from phenylsulfate esters to phenolic compounds. Pentachlorophenol, one of the selective inhibitors of phenol sulfoconjugation in mammalian tissues, inhibited both phenol and tyramine sulfation by ASST Nucleotide triphosphaies such as ATP, GTP, UTP and CTP, and pyrophosphate inhibited the ASST activity, whereas Mg²⁺ and Mn²⁺ activated the enzyme and prevented its inhibition by ATP and pyrophosphate. Equimolar binding of [α-] and [γ-³²P]ATP to the enzyme showed that the enzyme protein was not phospholylated, but bound ATP. These results suggest that nucleotide triphosphates and divalent cations are important modulators in the control of ASST activity.

Key Words: :

• Arylsulfate sulfotransferase
• nucleotides
• phenylsdfate esters
• ATP