HYDROPHOBIC INTERACTION AND FOLDING PROPENSITY OF CHICKEN HEART APOCYTOCHROME-C

In contrast to horse heart apocytochrome c, the chicken one showed qui te different folding propensity as titrated by NaCl at different pH. A t pH 2.0, folding behaviour of both apocytochrome c are essentially si milar; while at pH higher than 4.0, chicken heart apocytochrome c has much enhanced propensity to fold and aggregate, as was shown by circul ar dichroism spectra, intrinsic fluorescence and non-denatured. polyac rylamide gel electrophoresis. Hydrophobic chromatography demonstrated much higher hydrophobicity of chicken heart apocytochrome c, thus stro ngly suggested that it is the hydrophobic interaction that stabilize t he 'Molten Globule' like, partially-folded structure of chicken heart apocytochrome c at neutral pH.