[The functional state of denatured proteins: the principles of modelling and the first results].

The aqueous environment near cell membranes should be characterized by a local low pH value (due to attraction of protons by the membrane electrostatic potential) and by a local dielectric constant value (due to proximity of the water-organic boundary). It was proposed to simulate the behaviour of proteins near membranes by their behaviour in water-alcohol mixtures at moderately low pH values. Cytochrome c and retinol-binding protein are shown to be denatured at the values of pH and dielectric constant typical for the aqueous environment near the membrane surfaces. The conformational state of both these proteins under mentioned conditions is similar to the molten globule state. The basic function of the retinol-binding protein (transfer and release of vitamin A) is tightly associated with the transition of this carrier protein into the molten globule-like state, as in this case the release of retinol and protein denaturation are coupled and represent a common cooperative process.