title: Age-dependent modifications of rat heart succinate dehydrogenase.
abstract: The activity of rat heart succinate dehydrogenase (SDH) increases 1.7-fold in old animals (Vitorica, J., Cano, J., Satrústegui, J. and Machado, A., Mech. Ageing Dev., 16 (1981) 105-116). This increase is due to an increase in enzyme protein itself because: (a) the activation state of the enzyme does not vary with age; and (b) the increase of activity is paralleled by an increase in immunoprecipitable SDH in old rat heart mitochondria. SDH from old rat heart mitochondria differs in a number of ways from that of young animals: (a) The km value for succinate increases with age. (b) The thermostability decreases, and the activation energy in the 20-40 degrees C interval is higher in old animals. (c) The breaking points of the Arrhenius plots of SDH are shifted to higher values. (d) Reactivity towards N-ethylmaleimide in succinate protected mitochondria decreases with age.
mesh_terms: D000375:Aging; D000818:Animals; D000936:Antigen-Antibody Complex; D004789:Enzyme Activation; D004912:Erythrocytes / Q000201:enzymology; D005033:Ethylmaleimide / Q000494:pharmacology; D006321:Heart / Q000254:growth & development*; D007106:Immune Sera; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D013385:Succinate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000936:Antigen-Antibody Complex; D007106:Immune Sera; D013385:Succinate Dehydrogenase; D005033:Ethylmaleimide