NMR (Nuclear Magnetic Resonance) Relaxation of Water Protons under the Influence of Proteins and other Linear Polymers

摘要

The concept that water in living cells may exist in a physical state different from that of normal liquid water stimulated considerable interest in the nuclear magnetic resonance (NMR) relaxation times of water protons in living cells. The glow T sub 1 / T sub 2, as well as the high ratio of T1/T2 observed in living cells, led some scientists to the belief that the NMR data lent direct support to the association-induction hypothesis, according to which all or nearly all cell water exists in a state of polarized multilayers (PMW). A simple but efficient method of diagnosing PMW consists of exposing water to a matrix of fairly closely placed chains containing oxygen atoms, the distances between the nearest neighboring oxygen atoms being roughly equal to twice the diameter of a water molecule. Among the water-affecting polymers studied as matrices, the most intriguing is poly(ethylene oxide) (PEO) (-CH2-0-CH2)n because of its extreme simplicity; this polymer has no side chains whatsoever. Other effective polymers are polyvinyl-pyrrolidine (PVP), and gelatin. A series of studies of the NMR proton relaxation times of water in highly purified polymer-water systems has been carried out.