The activity of UDP-glucuronosyltransferase (UDPGT, EC 22.214.171.124) in human foetal liver cells in culture was measured with two acceptor substrates, namely harmol and 1-naphthol. There was a dose-dependent increase of about 10-400% in UDPGT activity when the cells were exposed to 1-30 microM-HgCl2. Above a critical concentration of 30 microM-HgCl2, the heavy metal ion was toxic to the cells. Kinetic studies of the glucuronidation reaction with harmol and 1-naphthol showed that Hg2+ ions seemed to induce the expression of a high-affinity form of UDPGT, which was absent from the normal controls. The dramatic increase in specific activity in UDPGT was accompanied by a parallel increase in Vmax. measured with harmol and UDP-glucuronic acid. The significance of a possible induction of UDPGT in human foetal liver cells by HgCl2 is discussed.
Expression of a high-affinity form of UDP-glucuronosyltransferase in human foetal liver cells in culture on exposure to mercuric chloride
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T M C Tan, K P Wong, K H Sit; Expression of a high-affinity form of UDP-glucuronosyltransferase in human foetal liver cells in culture on exposure to mercuric chloride. Biochem J 15 August 1991; 278 (1): 99–103. doi: https://doi.org/10.1042/bj2780099
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