| Abstract
| - The epoxidation of 1-hexene (1a) and 2-methyl-1-hexene (1b), two hydrocarbons present inthe ambient air as pollutants, is catalyzed by some human and rat P450 enzymes. Theenantioselectivities of these processes, when the reactions were carried out using rat and humanliver microsomal preparations, were modest and dependent on both P450 composition andsubstrate concentrations. Various P450 isoforms (rat P450 2B1 and human P450 2C10 and2A6) catalyzed the double bond oxidation of 1a and 1b with different product enantioselectivities. In the case of 1a, a moderately enantioselective hydroxylation at the allylic C(3) withthe formation of 1-hexen-3-ol (4a) by microsomes from control or preinduced rats was alsoobserved. The oxidation of this metabolite was, in turn, catalyzed by rat liver microsomesand mainly by rat P450 2C11, leading exclusively to the formation of 1-hexen-3-one, with nodouble bond epoxidation being observed. The stereochemical course of the microsomal epoxidehydrolase-catalyzed hydrolysis of the epoxy alcohols, threo-(±)- and erythro-(±)-1,2-epoxyhexan-3-ol, theoretically expected to be formed from 4a, has been investigated.
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