[Thermal stability of erythrocyte membrane proteins at varying ionic strength and media composition].

Varying the ionic strength and environmental composition differently affected the thermostability of certain protein blocks in the erythrocyte membrane. As the salt concentration in the solution enhanced, the redistribution of the system of intra- and intermolecular noncovalent bonds occurred, which induced changes in the membrane proteins structure resulting in an increase in the thermostability of both the integral and cytoplasmic band 3 domains and its associated band 4.2. The thermostability of the skeleton junction proteins (actin, 4.1 and 4.9) decreased. The thermostability of the spectrin changed insignificantly. The interaction of Mg2+ and Cu2+; but not Ca2+ ions with the membrane resulted in dynamic quenching the tryptophan fluorescence of the membrane proteins, unchanging their thermostability. Ca2+ ions induced the aggregation of erythrocyte membranes with increasing the temperature.