Product inhibition of o-aminophenol glucuronidation by p-nitrophenyl glucuronide in detergent-treated microsomal fractions.
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ABSTRACT: The glucuronidation of o-aminophenol is unaffected by p-nitrophenyl gluronide when native microsomal fractions are the source of UDP-glucuronyltransferase. When microsomal fractions treated with Lubrol detergent are the source of the enzyme, however, p-nitrophenyl glucuronide exhibits competitive inhibition of o-aminophenol glucuronidation. In addition, the apparent K1 for p-nitrophenyl glucuronide is the same whether o-aminophenol or p-nitrophenol is the acceptor substrate. The data suggest that UDP-glucuronyltransferase has one binding site for the two phenols and that the absence of inhibition observed in native microsomal fractions is dependent on an intact microsomal membrane.
SUBMITTER: Howland RD
PROVIDER: S-EPMC1186006 | biostudies-other | 1978 Sep
REPOSITORIES: biostudies-other
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