Metabolism of tetraorganolead compounds by rat-liver microsomal mono-oxygenase: II. Enzymic dealkylation of tetraethyl lead
- 1 January 1983
- journal article
- research article
- Published by Taylor & Francis in Xenobiotica
- Vol. 13 (10) , 583-590
- https://doi.org/10.3109/00498258309052217
Abstract
1. The biological degradation of tetraethyl lead to the triethyl lead cation by rat-liver microsomes from untreated, phenobarbital-pretreated and methylcholanthrene-pretreated rats has been studied; NADPH and oxygen are essential. 2. The reaction is inhibited by CO and can be reactivated in the presence of O2 by irradiation with u.v. light with a max. at 450nm. 3. Substrate binding to cytochrome P-450 is of type 1. 4. Apparent Km values for triethyl lead formation in microsomes were determined. The highest activities (i.e. about 2 nmol triethyl lead per nmol cytochrome P-450 per min) and the lowest apparent Km values (i.e. 7 × 10-6 M) are found in microsomes from methylcholanthrene-pretreated rats. 5. In microsomes from control and phenobarbital-pretreated rats Ks values from substrate-binding studies (about 2 × 10-6M) are one order of magnitude lower than the apparent Km values (3 × 10-5 M).Keywords
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