| Popis: |
In this work, the proton spin-lattice (T-1) and spin-spin (T-2) relaxation times of aqueous solutions of bovine serum albumin (BSA) were investigated as a function of temperature. The T-1 relaxation times were measured versus temperature (T) for five H2O solutions containing different BSA concentrations. The sample temperature was varied from 304 to 253 K for each concentration. T-2 measurements were carried out versus the BSA concentrations only. The least-square fitting of ln(T-1) versus T-1 yields a linear correlation. The effective correlation times tau(1) for T-1 and tau(2) for T-2 were calculated by using experimental data and the related theory. The data suggest that surface water is responsible for the dipolar relaxation mechanisms. Both T-1 and T-2 mechanisms are caused by overall tumbling of albumin molecule causing the rotational correlation time. However, some slow motions may contribute to the T-2 mechanism. |
