QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gecha, O. M. Articles by Fagan, J. M. Search for Related Content PubMed PubMed Citation Articles by Gecha, O. M. Articles by Fagan, J. M.

Protective Effect of Ascorbic Acid on the Breakdown of Proteins Exposed to Hydrogen Peroxide in Chicken Skeletal Muscle¹

Department of Animal Sciences, Rutgers University, New Brunswick, NJ 08903

Ascorbic acid is believed to protect cells from oxidative damage by reacting with oxygen-derived free radicals. We investigated whether ascorbic acid would affect the rate of breakdown of skeletal muscle proteins in extracts exposed to hydrogen peroxide. Ascorbic acid (20 mmol/L) alone had little or no effect on the rate of ATP-independent or ATP-dependent breakdown of proteins in chicken skeletal muscle. Pretreatment of chicken skeletal muscle extracts with 10 mmol/L H₂O₂ resulted in a complete loss of ATP-dependent proteolysis and a significant increase (14- to 15-fold) in the rate of ATP-independent protein breakdown. Ascorbic acid (20 mmol/L) did not prevent H₂O₂ (10 mmol/L) from inactivating the ATP-dependent proteolytic pathway in skeletal muscle. However, ascorbic acid (20 mmol/L) prevented the H₂O₂-induced increase in the ATP-independent proteolysis of endogenous muscle proteins. Ascorbic acid also slowed the rate of hydrolysis of exogenously added [³H]superoxide dismutase exposed to H₂O₂ and inhibited the enhanced degradation of [³H]lysozyme and H₂O₂-treated [³H]superoxide dismutase by the proteolytic systems exposed to H₂O₂. Thus ascorbic acid seems to inhibit the H₂O₂-induced increase in ATP-independent proteolysis 1) by preventing damage to proteins by H₂O₂ resulting in a decreased supply of substrates for the ATP-independent degradative system and 2) by preventing activation of the proteolytic enzymes that participate in the energy-independent degradation of H₂O₂-treated proteins.

KEY WORDS: • ascorbic acid • hydrogen peroxide • skeletal muscle protein breakdown • chickens

¹ This work was conducted during the tenure of an established investigatorship of the American Heart Association awarded to J.M.F and was supported by research grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases, USDA, American Heart Association, Rutgers University and the New Jersey Agricultural Experiment Station, which is supported by State funds.

² To whom correspondence should be addressed.

Manuscript received 9 March 1992. Revision accepted 25 June 1992.