5-乙炔基-2'-脱氧尿苷酸与胸苷酸合成酶的相互作用。

Interaction of 5-ethynyl-2'-deoxyuridylate with thymidylate synthetase.

作者信息

Danenberg P V, Bhatt R S, Kundu N G, Danenberg K, Heidelberger C

出版信息

J Med Chem. 1981 Dec;24(12):1537-40. doi: 10.1021/jm00144a036.

Abstract

The interaction of 5-ethynyl-2'-deoxyuridylate (5-ethynyl-dUMP; 1) with thymidylate (dTMP) synthetase has been investigated. The compound was an inhibitor of the enzyme, competitive with 2'-deoxyuridylate (dUMP) when the reaction was initiated by addition of enzyme (Ki = 2.7 X 10(-6) M). However, upon preincubation of 1 with dTMP synthetase, the inhibition pattern became noncompetitive. The time course of the enzyme reaction in the presence of 1 was nonlinear, indicating an increase in binding with time. Irreversible inactivation of the enzyme did not occur. The compound did not appear to become altered structurally as a result of interaction with the enzyme. A ternary complex was formed among dTMP synthetase, compound 1, and 5,10-methylenetetrahydrofolate, which was stable enough to survive Sephadex G-25 filtration but dissociated upon denaturation of the enzyme.

摘要

已对5-乙炔基-2'-脱氧尿苷酸（5-乙炔基-dUMP；1）与胸苷酸合成酶的相互作用进行了研究。该化合物是该酶的抑制剂，当通过添加酶启动反应时，它与2'-脱氧尿苷酸（dUMP）竞争（Ki = 2.7×10⁻⁶ M）。然而，在1与胸苷酸合成酶预孵育后，抑制模式变为非竞争性。在存在1的情况下酶反应的时间进程是非线性的，表明结合随时间增加。酶未发生不可逆失活。该化合物似乎不会因与酶相互作用而在结构上发生改变。在胸苷酸合成酶、化合物1和5,10-亚甲基四氢叶酸之间形成了三元复合物，该复合物足够稳定，能够经受住葡聚糖凝胶G-25过滤，但在酶变性后解离。