Inter- and intramolecular deuterium isotope effects on the cytochrome P-450-catalyzed oxidative dehalogenation of 1,1,2,2-tetrachloroethane

Journal Article · Wed Dec 16 00:00:00 EST 1987 · Biochem. Biophys. Res. Commun.; (United States)

DOI:https://doi.org/10.1016/0006-291X(87)90369-X· OSTI ID:5347519

Hales, D B; Ho, B; Thompson, J A

The oxidation of 1,1,2,2-tetrachloroethane to dichloroacetic acid was investigated with rat liver microsomes and purified cytochrome P-450. Deuterium substitution had no effect on Km values, but both the inter- and intramolecular isotope effects (kH/kD) on Vmax were in the range 5.7-6.1. The equivalence of the inter- and intramolecular values indicates that 6.0 may be a good estimate of the intrinsic isotope effect. The intermolecular kH/kD value for the conversion of 1,1,2,2-trichloroethane and its 1-/sup 2/H analog to chloroacetic acid was 5.5. These data, and the finding that 1 atom of /sup 18/O was incorporated into the product when TCEA was oxidized in an /sup 18/O/sub 2/ atmosphere, support an oxidative dechlorination mechanism that involves hydrogen atom abstraction by the P-450 intermediate oxo complex.

• Research Organization: Univ. of Colorado, Boulder
• OSTI ID: 5347519
• Journal Information: Biochem. Biophys. Res. Commun.; (United States), Vol. 149:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
CHLORINATED ALIPHATIC HYDROCARBONS
METABOLIC ACTIVATION
DEUTERIUM
ISOTOPE EFFECTS
CYTOCHROMES
ETHANE
IN VITRO
LIVER
MICROSOMES
OXYGEN 18
RATS
REDOX REACTIONS
TRACER TECHNIQUES
ALKANES
ANIMALS
BODY
CELL CONSTITUENTS
CHEMICAL REACTIONS
DIGESTIVE SYSTEM
EVEN-EVEN NUCLEI
GLANDS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANOIDS
ORGANS
OXYGEN ISOTOPES
PIGMENTS
PROTEINS
RODENTS
STABLE ISOTOPES
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550501 - Metabolism- Tracer Techniques