title: Kinetics of metabolism of propene and covalent binding to macromolecules in the mouse.
abstract: The rate of uptake of propene from air was studied by exposing CBA mice to various concentrations of the gas in a closed, recirculating all-glass chamber. The rate curves showed a saturable dependence on the propene concentration. The inhalational Km and Vmax were calculated to be 800 +/- 60 ppm and 8 +/- 0.5 mg (kg body wt)-1 hr-1, respectively, from a Lineweaver-Burk plot of the rate data. The homologous compound ethene is known to be metabolized in the mouse to ethene oxide. When a trace amount of 14C-labeled ethene was administered in combination with a high concentration of propene, the uptake of [14C]ethene was lower than in the absence of propene, suggesting a competitive interaction in their metabolic pathways. One group of animals were exposed at 20,000 ppm of propene 4 hr/day during 8 consecutive days. Hemoglobin was isolated from the treated group and a control group. After hydrolysis of the protein, two diastereomers of N tau-(2-hydroxypropyl)histidine were identified in the hydrolysate from treated animals, suggesting that propene, analogous to ethene, is metabolized to the corresponding epoxide and showing that the oxidation is not stereospecific. 2-Hydroxypropylated products were found in hemoglobin from mice treated with 14C-labeled propene. The amounts of alkylated products in DNA were below the detection limit.
mesh_terms: D000475:Alkenes / Q000378:metabolism*; D000478:Alkylation; D000818:Animals; D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D004852:Epoxy Compounds / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances / Q000378:metabolism; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA
chemical_list: D000475:Alkenes; D004852:Epoxy Compounds; D006454:Hemoglobins; D046911:Macromolecular Substances; D004247:DNA; C013658:propylene; C009068:propylene oxide