White M W, Vandenbark A A, Barney C L, Ferro A J
Biochem Pharmacol. 1982 Feb 15;31(4):503-7. doi: 10.1016/0006-2952(82)90151-4.
5'-Deoxy-5'-methylthioadenosine (MTA) phosphorylase was purified 13.4-fold from human peripheral lymphocytes. The enzyme demonstrated normal Michaelis-Menten kinetics with Km values of 26 microM and 7.5 mM for the two substrates, MTA and phosphate, respectively. The rate of MTA degradation was temperature dependent, 47 degrees being the optimum temperature. Five structural analogs served as alternative substrates with Km values ranging from 31 to 53 microM while two compounds, 5'-deoxy-5'-methylthiotubercidin (MTT) (Ki = 31 microM) and adenine (Ki = 172 microM), were inhibitory. These same analogs were examined as inhibitors of mitogen-induced human lymphocyte blastogenesis. MTT was found to be the most effective inhibitor of lymphocyte transformation with an I50 of 80 microM.
5'-脱氧-5'-甲硫基腺苷（MTA）磷酸化酶从人外周血淋巴细胞中纯化出来，纯化倍数为13.4倍。该酶对两种底物MTA和磷酸盐表现出正常的米氏动力学，其Km值分别为26微摩尔和7.5毫摩尔。MTA降解速率取决于温度，最适温度为47摄氏度。五种结构类似物可作为替代底物，其Km值在31至53微摩尔之间，而两种化合物5'-脱氧-5'-甲硫基杀结核菌素（MTT）（Ki = 31微摩尔）和腺嘌呤（Ki = 172微摩尔）具有抑制作用。这些相同的类似物被作为有丝分裂原诱导的人淋巴细胞增殖的抑制剂进行检测。发现MTT是淋巴细胞转化最有效的抑制剂，其半数抑制浓度（I50）为80微摩尔。
