Effect of nucleotides on thermal stability of ferricytochrome C.
The effect of nucleotides on the structure and thermal stability of ferricytochrome c was studied by differential scanning calorimetry. The association of cytochrome c with ATP and ADP resulted in a decrease in the denaturation temperature of cytochrome c by 7 degrees C and 4 degrees C, respectively, at pH 7.0. AMP did not change the denaturation temperature of cytochrome c at pH 7.0. The ratio between van't Hoff and calorimetric enthalpy of denaturation accounts for the fact that cooperative denaturation of 3-4 molecules of cytochrome c occurred in the presence of ATP at the pH range from 5 to 9. ADP gave rise to the interaction of 2-3 molecules of ferricytochrome c at pH 6-7.5, and AMP did not affect the interaction of protein molecules. Cytochrome c alone also associated at pH 7.5-10. At physiological ionic strength, pH 7.0, only ATP induced an association of ferricytochrome c molecules. No intermolecular interaction of ferricytochrome c molecules was observed at concentrations of NaCl higher than 0.2 mol/l not even in the presence of ATP.
Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice.
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Bágel'ová
D000227:Adenine Nucleotides / Q000494:pharmacology; D000818:Animals; D002152:Calorimetry, Differential Scanning; D003570:Cytidine Triphosphate / Q000494:pharmacology; D003574:Cytochrome c Group / Q000737:chemistry / Q000378:metabolism*; D004355:Drug Stability; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006736:Horses; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D015394:Molecular Structure; D009711:Nucleotides / Q000494:pharmacology*; D011489:Protein Denaturation / Q000187:drug effects; D013696:Temperature; D013816:Thermodynamics; D014544:Uridine Triphosphate / Q000494:pharmacology
D000227:Adenine Nucleotides; D003574:Cytochrome c Group; D009711:Nucleotides; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D014544:Uridine Triphosphate