Peroxidatic oxidation of benzo(a)pyrene and prostaglandin biosynthesis
The arachidonic acid dependent oxidation of benzo(a)pyrene to a mixture of 3,6-, 1,6-, and 6,12-quinones has been studied by using enzyme preparations from sheep seminal vesicles. Maximal oxidation is observed at 100 ..mu..M benzo(a)pyrene and 150 ..mu..M arachiodinic acid. The arachidonic acid dependent oxidation is peroxidatic and utilizes prostaglandin G/sub 2/ (PGG/sub 2/), generated in situ from arachidonate, as the hydroperoxide substrate. 15-Hydroperoxy-5,8,11,13-eicosatetraenoic acid is equivalent to PGG/sub 2/ as a hydroperoxide substrate, but hydrogen peroxide, cumene hydroperoxide, and tert-butyl hydroperoxide are much poorer substrates. Arachidonic acid dependent benzo(a)pyrene oxidation by microsomal and solubilized enzyme preparations is markedly stimulated by a variety of hemes and heme proteins. This is not due to the previously reported heme stimulation of prostaglandin biosynthesis (Yoshimoto, A., Ito, H., and Tomita, K. (1970) J. Biochem. (Tokyo) 68, 487-499). Instead, the hemes function directly as peroxidases utilizing fatty acids hydroperoxides as substrates. The incubation of PGG/sub 2/ with commercial methemoglobin in the absence of any other protein gives rise to significant benzo(a)pyrene oxidation to quinones. The widespread occurrence of heme proteins in animal tissue suggests that the peroxidatic oxidation of benzo(a)pyrene will be significant in any tissue that makes appreciable concentrations of fatty acid hydroperoxides.
- Research Organization:
- Wayne State Univ., Detroit, MI
- OSTI ID:
- 5465114
- Journal Information:
- Biochemistry; (United States), Vol. 18:14
- Country of Publication:
- United States
- Language:
- English
Similar Records
Prostaglandin synthetase dependent benzo(a)pyrene oxidation: products of the oxidation and inhibition of their formation by antioxidants
Benzo(a)pyrene metabolism by murine spleen microsomes
Related Subjects
BENZOPYRENE
METABOLIC ACTIVATION
OXIDATION
PROSTAGLANDINS
BIOSYNTHESIS
ARACHIDONIC ACID
CARBON 14 COMPOUNDS
EXPERIMENTAL DATA
GRAPHS
HEME
HYDROGEN PEROXIDE
METABOLISM
METHEMOGLOBIN
PEROXIDASES
QUINONES
SHEEP
TABLES
TRITIUM COMPOUNDS
ANIMALS
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CONDENSED AROMATICS
DATA
DATA FORMS
DOMESTIC ANIMALS
ENZYMES
GLOBIN
HEMOGLOBIN
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
LABELLED COMPOUNDS
MAMMALS
MONOCARBOXYLIC ACIDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PEROXIDES
PIGMENTS
PORPHYRINS
PROTEINS
RUMINANTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques