[NMR spin-echo study of behaviour dynamics of serum albumin macromolecules in aqueous solutions as a function of pH and ionic strength].

Alteration of the intermolecular interaction in aqueous solution of human serum albumin (SA) as a result of the increase of ionic strength and pH values brings about the slowing-down of the spin-echo decay curve for protein protons (several times at high SA concentrations). A specific effect of alkaline pH was observed, i.e. the slowing-down of quick component of the spin-echo decay curve. This result taken together with the data on complex spin-echo decay curve, correlation times of protons of different regions is SA and compared with SA isotope exchange data can be explained as a result of the polypeptide chain conformation mobility with frequencies more 10(4) c.p.s. This effect is observed in regions occupying about one half of the SA macromolecule volume.