NMR studies of 23Na+ in frozen bovine serum albumin solution

Abstract

An NMR investigation of the dynamics of sodium ions in the residual non-freezing water in bovine serum albumin solutions cooled to below freezing points is described. Measurements of signal intensities and transverse relaxation times indicated that all of the sodium is concentrated into the non-freezing water and that correlation times are of the same order as those in water at protein interfaces. It is concluded that non-freezing water, therefore, is likely to be a medium in which chemical reactions can readily take place.