title: Inhibition of ascorbate autoxidation by the dialyzed soluble fraction of mammalian nervous tissues.
abstract: The effect of the soluble fraction of mammalian nervous tissue was tested on the autoxidation of ascorbic acid in a physiological salt solution. Ascorbic acid was determined spectrophotometrically at 265 nm. Tissues tested were from humans and guinea pigs (ascorbate-dependent species); cats, rats and mice (ascorbate-synthesizing species). Samples representing the major anatomical areas of the CNS and adrenal glands were homogenized in phosphate buffer (10% w/v), centrifuged at 100,000 g for 60 min and the supernatant was dialyzed in 25,000 mol.wt. cut-off tubing. The preparations produced basically uniform inhibitory activity: extracts at 10(4)-fold dilution reduced the rate of autoxidation by approximately 90%. The effect was marginal at 5 X 10(4)-fold dilution. Serum samples displayed similar activity. The results indicate that mammalian nervous tissue and serum contain a substance of relatively large molecular weight that stabilizes reduced ascorbic acid against oxidative breakdown.
mesh_terms: D000368:Aged; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D002415:Cats; D002540:Cerebral Cortex / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D006168:Guinea Pigs; D006801:Humans; D007700:Kinetics; D051379:Mice; D009928:Organ Specificity; D010084:Oxidation-Reduction; D051381:Rats; D013045:Species Specificity; D013116:Spinal Cord / Q000378:metabolism*
chemical_list: D001205:Ascorbic Acid