Enzyme specific kinetics of 1,2-epoxybutene-3 in microsomes and cytosol from livers of mouse, rat, and man.

Abstract

Kinetics of the metabolism of 1,2-epoxybutene-3 (butadiene monoxide) were investigated in liver fractions of mouse, rat, and man. In these species similar enzyme characteristics were found. In microsomes, no NADPH-dependent metabolism of butadiene monoxide was detectable. Epoxide hydrolase activity was found only in microsomes. The Vmax [nmol butadiene monoxide/(mg protein x min)] was 19 in mouse, 17 in rat, and 14 in man and the apparent Km (mmol butadiene monoxide/l incubate) was 1.5 in mouse. 0.7 in rat, and 0.5 in man. Glutathione S-transferase activity was found in cytosol only, revealing first order kinetics in the measured range. The ratio Vmax/Km [(nmol butadiene monoxide x 1)/(mg protein x min x mmol of butadiene monoxide)] was 15 in mouse, 11 in rat, and 8 in man. The data obtained were used to extrapolate on the total rate of butadiene monoxide metabolism for each species in vivo: it was calculated to be 1.3 times higher in mice and 2.3 times lower in man compared to rats, when corrected for body weight.

• Authors: P E Kreuzer, W Kessler, H F Welter, C Baur, J G Filser
• Journal: Archives of toxicology (Arch Toxicol) Vol. 65 Issue 1 Pg. 59-67 ( 1991) ISSN: 0340-5761 [Print] Germany
• PMID: 2043052 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Epoxy Compounds
• 3,4-epoxy-1-butene

Topics

• Animals
• Chromatography, Gas
• Cytosol (metabolism)
• Epoxy Compounds (pharmacokinetics)
• Humans
• In Vitro Techniques
• Liver (metabolism)
• Male
• Mice
• Microsomes, Liver (metabolism)
• Rats
• Rats, Inbred Strains
• Species Specificity