Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:6094-02-6 (C7H14)
 9 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rabbit liver microsomal biotransformation of alpha-methylstyrene (1a), 2-methyl-1-hexene (1b), 2,4,4-trimethyl-1-pentene (1c), and 1,3,3-trimethyl-1-butene (1d) has been investigated with the aim at establishing the enantioface selection of the cytochrome P-450-promoted epoxidation of the double bond and the enantioselectivity of microsomal epoxide hydrolase(mEH)-catalyzed hydrolysis of the resulting epoxides. GLC on a Chiraldex G-TA (ASTEC) column was used to determine the enantiomeric composition of the products. The epoxides 2 first produced in incubations carried out in the presence of an NADPH regenerating system were not detected, being rapidly hydrolyzed by mEH to diols 3. The enantiomeric composition of the latter showed that no enantioface selection occurred in the epoxidation of 1c and 1d, and a very low (8%) ee of the (R)-epoxide was formed from 1b. Incubation of racemic epoxides 2b-d with the microsomal fraction showed that the mEH-catalyzed hydrolysis of 2c and 2d was practically nonenantioselective, while that of 2b exhibited a selectivity E = 4.9 favoring the hydrolysis of the (S)-enantiomer. A comparison of these results with those previously obtained for linear and branched chain alkyl monosubstituted oxiranes shows that the introduction of the second alkyl substituent suppresses the selectivity of the mEH reaction of the latter and reverses that of the former substrates.
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PMID:The rabbit liver microsomal biotransformation of 1,1-dialkylethylenes: enantioface selection of epoxidation and enantioselectivity of epoxide hydrolysis. 802 51

The epoxidation of 1-hexene (1a) and 2-methyl-1-hexene (1b), two hydrocarbons present in the ambient air as pollutants, is catalyzed by some human and rat P450 enzymes. The enantioselectivities of these processes, when the reactions were carried out using rat and human liver microsomal preparations, were modest and dependent on both P450 composition and substrate concentrations. Various P450 isoforms (rat P450 2B1 and human P450 2C10 and 2A6) 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) with the formation of 1-hexen-3-ol (4a) by microsomes from control or preinduced rats was also observed. The oxidation of this metabolite was, in turn, catalyzed by rat liver microsomes and mainly by rat P450 2C11, leading exclusively to the formation of 1-hexen-3-one, with no double bond epoxidation being observed. The stereochemical course of the microsomal epoxide hydrolase-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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PMID:Stereochemistry of the biotransformation of 1-hexene and 2-methyl-1-hexene with rat liver microsomes and purified P450s of rats and humans. 986 Apr 92