新的水溶性^(13)C NMR弛豫试剂的性质研究

SUTDY OF PROPERTY OF NEW WATER-SOLUBLE ^(13)C NMR RELAXATION REAGENT

合成了Gd^(3+)与2,3-二羟基-对-二甲苯胺四乙酸(DPTA)的固体配合物,研究了该化合物作为水溶性^(13)NMR弛豫试剂的性质,证明该试剂对增强各种氨基酸(苏氨酸、半胱氨酸、精氨酸、组氨酸、色氨酸和抗坏血酸)季碳原子的谱峰强度是十分有效的。精氨酸的自旋-晶格弛豫时间(T_1)测量表明,Gd-DPTA可使精氨酸分子中季碳T_1缩短200倍以上,效果优于Gd-DTPA。

Soid complex of Gd1- with 2, 3-dihydroxy-p-xylylenf diaminotetraacetic acid (DPTA) was synthesized. Studies have been performed in which the above-mentioned complex was utilized as water-soluble paramagnetic relaxation reagent for 13C NMR spectrometry. Model compounds with which the reagent is effective include threonine, cysteine, arginine, histidine, tryptophan and ascorbic acid. It was shown that the reagent investigated can not only enhance the singal intensities for carbons not attached to hydrogen, but also suppress the nuclear Overhauser effect (NOE) for protonated carbons. Carbons-13 spin-lattice relaxation times (Ti)of the arginine acid in the presence or absence of the relaxation reagents were measured. The results show that Gd-DPTA is more effective than Gd-DTPA as a carbon-13 relaxation reagent.