Lester C C, Bryant R G
Department of Chemistry, University of Rochester, New York 14623.
Magn Reson Med. 1992 Apr;24(2):236-42. doi: 10.1002/mrm.1910240205.
Measurements of the spin-lattice relaxation rates of water protons made over a wide frequency range have demonstrated that the effects of paramagnetic relaxation agents may be considerably enhanced when the paramagnetic center is incorporated into a compact structure macromolecule such as a protein that is rotationally constrained. The immobilization of the macromolecule profoundly changes the nature of the magnetic field dependence of the relaxation rate for both the diamagnetic and the paramagnetic samples. The immobilization also amplifies the effect of the paramagnetic center as a water-proton relaxation agent. The direct exchange of labile water molecules or protons is not a requirement for the high efficiency of this class of magnetic relaxation agents.
在很宽的频率范围内对水质子的自旋晶格弛豫率进行测量表明，当顺磁中心被纳入紧密结构的大分子（如旋转受限的蛋白质）中时，顺磁弛豫剂的效果可能会显著增强。大分子的固定化深刻改变了抗磁和顺磁样品弛豫率对磁场依赖性的性质。固定化还增强了顺磁中心作为水质子弛豫剂的作用。这类磁弛豫剂的高效性并不要求不稳定水分子或质子的直接交换。
