[Properties of globular protein monolayers at physiological temperature intervals]

The dynamics of changes in monolayer (MML) static and kinematic characteristics of some globular proteins (humans' serum, albumin, actin, cytochrome c) was studied. Two series of experiments were carried out: 1) formation of MML at the stable temperature of subphase 12, 23 and 32 degrees C; 2) formation of MML at 12 degrees C and equilibrium warming up and following cooling of subphase with MML in the temperature interval of 12-34 degrees C. In the cooling-warming up cycle the dependence of MML surface pressure change on the temperature was found to have the form of reserved loop hysteresis with the minimum at 21 +/- 2 degrees C on warming up branch. By the following rise of temperature up to reaching the plateau (26 degrees C) the entropy of monolayer takes the negative meaning. On the branch of cooling loop such transition is not seen. These data indicate possibility of trigger conformative changes of protein molecules, which in situ condition can occur during the natural local (metabolic) temperature gradients in living cells and influence the functional specificity of protein molecules and their bioorganic complexes.