[Study of interaction between alcohols (mono- and polhydric) and proteins in aqueous solutions]

Phosphorescence properties of protein aqueous solutions (life-time, bend-point on the plots of life-time v. s. temperature, maximum positions in spectra, intensity) were shown to depend upon the concentration in the solution of solute--additions (mono- and polyhydric alcohols, glucose, sucrose, certain amino acids). New parameter tau--average life-time of protein phosphorescence in the persence in the solution of the iodine ion constant concentration, was proposed. By the character of dependence of this parameter upon the solute-addition concentration all solutes, which were used as additions, may be devided into two classes. A rise in the solution of the first class additions (monohydric alcohols) was followed by an increase of tau, that evidences for a decrease in availability of protein tryptophanyls, which may be a result of the adsorption of solute-addition by protein. With the addition concentration about 0.5% tau passes through maximum and then decreases. An increase in the solution of the second class addition (glycol, glycerol, polyethylenglycol, glucose, surcrose) was followed by a decrease of tau, that indicates to an increase of trypophanyl availability, Such an interaction of additions with protein is typical of papain and fibrinogen. In the case of myosin the addition of the second class solutes causes a sharp increase of tau with their sufficient concentration. The obtained results make it possible to state that the solute-additions affect proteins directly besides their indirect influence by a change in the water structure.