Product inhibition of o-aminophenol glucuronidation by p-nitrophenyl glucuronide in detergent-treated microsomal fractions.
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.
D000627:Aminophenols / Q000378:metabolism*; D000818:Animals; D003902:Detergents / Q000494:pharmacology*; D005965:Glucuronates / Q000378:metabolism* / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D009578:Nitrobenzenes / Q000494:pharmacology; D051381:Rats
D000627:Aminophenols; D003902:Detergents; D005965:Glucuronates; D009578:Nitrobenzenes