Bunni M A, Douglas K T
Biochem J. 1984 Jan 15;217(2):383-90. doi: 10.1042/bj2170383.
The use of organothallium compounds for protein/macromolecule modification and as probes for n.m.r. and fluorescence is introduced. Lactate dehydrogenase from a number of species was rapidly and specifically inhibited by o-carboxyphenylthallium(III) bistrifluoroacetate and p-methylphenylthallium(III) bistrifluoroacetate. Inhibition of rabbit muscle lactate dehydrogenase by o-carboxyphenylthallium(III) bistrifluoroacetate was time-dependent and not reversible by gel filtration. A small degree of re-activation was possible by incubation with dithiothreitol. The time course of the inactivation kinetics showed two phases, only the first, and faster, of which was efficiently prevented by the presence of cofactor, NADH. Inhibition rates depended on the structure of the thallium reagent, its concentration and the temperature. No significant inhibition was found by thallous acetate or thallic trifluoroacetate. Saturation kinetics were observed for the inhibition by o-carboxyphenylthallium(III) bistrifluoroacetate of the pig heart enzyme. The possibilities of various cross-linking activities of these reagents are addressed. Mechanisms of the inhibition are discussed.
介绍了有机铊化合物在蛋白质/大分子修饰以及作为核磁共振和荧光探针方面的应用。多种来源的乳酸脱氢酶可被邻羧基苯基铊（III）双三氟乙酸酯和对甲基苯基铊（III）双三氟乙酸酯迅速且特异性地抑制。邻羧基苯基铊（III）双三氟乙酸酯对兔肌肉乳酸脱氢酶的抑制作用具有时间依赖性，且通过凝胶过滤不能逆转。与二硫苏糖醇孵育可实现一定程度的重新激活。失活动力学的时间进程呈现两个阶段，其中只有第一个且较快的阶段能被辅因子NADH有效阻止。抑制速率取决于铊试剂的结构、其浓度和温度。乙酸亚铊或三氟乙酸铊未发现明显抑制作用。观察到邻羧基苯基铊（III）双三氟乙酸酯对猪心酶的抑制呈现饱和动力学。探讨了这些试剂各种交联活性的可能性。讨论了抑制机制。
