Iino M
Department of Physiology, Nippon Medical School, Tokyo, Japan.
Magn Reson Med. 1994 Oct;32(4):459-63. doi: 10.1002/mrm.1910320406.
Magnetization transfer experiments using an off-resonance irradiation technique were performed on bovine serum albumin solutions by varying the irradiation frequency and the concentration. A transition of the magnetization transfer spectrum from Lorentzian to Gaussian line shape was observed around the critical concentration of 6.2 mmoles of protein to kg of solution. Observed magnetizations were well expressed by the rate equations of populations for spins below and above the transition, which yielded the magnetization transfer rates, the intrinsic relaxation rates of both protein and water protons, and the effective tumbling time and the rigid line width of the protein. The result showed that the estimates of the values for magnetization transfer rate do not change once the critical concentration is reached.
利用偏离共振照射技术对牛血清白蛋白溶液进行了磁化转移实验，通过改变照射频率和浓度来进行。在每千克溶液中蛋白质为6.2毫摩尔的临界浓度附近，观察到磁化转移谱从洛伦兹线型向高斯线型的转变。低于和高于转变点的自旋态的速率方程能够很好地描述观察到的磁化强度，由此得到了磁化转移速率、蛋白质和水质子的固有弛豫速率、蛋白质的有效翻滚时间和刚性线宽。结果表明，一旦达到临界浓度，磁化转移速率值的估计就不会改变。
