NMR of water in biological systems

Abstract

An extensive investigation of water NMR response in the muscular tissue (frog gastrocnemius) is presented. Our data are compared with the predictions of the «cage models» (discussed in a companion paper), which envisions a single water phase subjected to topological constraints. Several features of the NMR response are easily accounted for by the cage models. Instead, other features give clear evidence for the existence of different phases of water. We performed also an analysis of NMR data for biological and model systems studied in the literature. We suggest that, in most cases, it is more appropriate to interpret NMR data in terms of a single water phase with an average mobility somewhat reduced with respect to that of free water, rather than in terms of several ill-characterized phases.