Effect of ionic strength on the interfacial properties of cytochrome c.
The surface tension behaviour of oxidised cytochrome c (cyt c) solution was characterised at various pH and ionic strength at the air/water interface. The pendant drop method employing digital image analysis of the drop shape was applied to the measurement of the surface tension. The adsorption properties of cyt c were utilised to study the protein conformation change effected by acidification and ionic strength. At high ionic strength, the saturated steady-state surface tension shows a cooperative change centred around 3.6 induced by a decrease in pH. Using spectroscopic experiments, the apparent pK of the acid-induced transition of horse cyt c from the native to the molten globular state is equal to 3.5. This fact indicates that the saturated steady-state surface tension is a parameter which might be used to monitor conformation changes of cyt c.
Gazová
Z
Z
Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 043 53, Kosice, Slovakia.
Antalík
M
M
Bágel'ová
J
J
Tomori
Z
Z
D003574:Cytochrome c Group / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D011487:Protein Conformation; D012996:Solutions; D013500:Surface Tension
D003574:Cytochrome c Group; D012996:Solutions