Phenol sulfotransferases (PSTs, EC 2.8.2.1) catalyze sulfonyl group transfe
r from 3'-phosphoadenosine-5'-phosphosulfate (PAPS) to the hydroxyl oxygen
of aromatic acceptor substrates. The structural overlap between PAPS and co
enzyme A (CoA) suggested a possible role of this common acyl carrier in mod
ulating PST activity. To test this hypothesis, purified recombinant bovine
PST was examined by kinetic and affinity chromatographic approaches. After
demonstrating PST enzyme inhibition by CoA, systematic variation of CoA and
PAPS concentrations indicated simple competitive inhibition with K-i = 1.3
mu M. PST bound to CoA-agarose, attached via the pantetheinyl thiol group,
was eluted with PAP but not by a-naphthol. This observation was consistent
with the pattern of inhibition. Additional members of the sulfotransferase
superfamily, as well as acylated CoAs, should be further investigated. (C)
1999 Academic Press.