Ascorbic acid metabolism in protection against free radicals: A radiation model
- Univ. of North Dakota, Grand Forks (USA)
The role of ascorbic acid in scavenging free radicals was evaluated in a model of mammalian colonic epithelium homogenized in physiologic buffer and exposed to ionizing radiation. Ascorbic acid interacts with hydroxyl free radicals, resulting in production of the ascorbate free radical (AFR). Colonic mucosa contains a soluble factor that is heat sensitive, PCA precipitable and is contained within 1,000 MW dialysis tubing; it uses GSH and cysteine to reduce AFR. The factor from rat colon is fractionated between 55 and 70% saturation with solid (NH4)2SO4; a 3-4 fold increase in enzyme activity was achieved. We suggest that the factor is a cytosolic enzyme appropriately referred to as soluble AFR-reductase. This information provides insight into the mechanism by which ascorbic acid protects against damage by hydroxyl free radicals.
- OSTI ID:
- 7062359
- Journal Information:
- Biochemical and Biophysical Research Communications; (USA), Vol. 169:2; ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ASCORBIC ACID
METABOLISM
OXIDOREDUCTASES
ENZYME ACTIVITY
RADICALS
BIOSYNTHESIS
CYSTEINE
EPITHELIUM
IONIZING RADIATIONS
LARGE INTESTINE
MAN
MUCOUS MEMBRANES
NADH2
RADIOSENSITIVITY EFFECTS
RATS
REDOX REACTIONS
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BODY
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
COENZYMES
DIGESTIVE SYSTEM
ENZYMES
GASTROINTESTINAL TRACT
INTESTINES
MAMMALS
MEMBRANES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PRIMATES
RADIATIONS
RODENTS
SYNTHESIS
THIOLS
TISSUES
VERTEBRATES
VITAMINS
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture