Pulsed Nuclear Magnetic Resonance Studies of Water in Myosin Suspension during Dehydration

抄録

Pulsed NMR was applied to measure the spin-lattice(T₁) and spin-spin(T₂) relaxation times of water protons in myosin suspension with or without sucrose during the course of its dehydration. T_l relaxation time curves showed two phase behaviour at the high moisture contents. Plots of T₁ as a function of moisture content showed minima in the multilayer region (in the range of 18.5_??_24% moisture contents), irrespective of the presence or absence of sucrose in the system. On the other hand, irrespective of the presence or absence of sucrose, T₂ relaxation time curves of myosin containing more than 89_??_91% of water exhibited a three phase behaviour, indicating the existence of three water fractions of different mobility (T_2-A, T_2-B and T_2-C). The amount of water in the bound fraction (T_2-B+T_{2_??_C}) showed a consistency until the free water fraction (T_{2_??_A}) is almost removed. T₂ values of three water fractions were found to decrease with a decrease in the moisture content, and these values as well as the populations of three classes of water protons did not show the significant difference between samples in the presence and absence of sucrose throughout the course of dehydration process.