Musso-Buendía Juan A, Vidal Antonio E, Kasinthan Ganasan, Nguyen Corinne, Carrero-Lérida Juana, Ruiz-Pérez Luis M, Wilson Keith, Johansson Nils Gunnar, Gilbert Ian H, González-Pacanowska Dolores
Instituto de Parastiologia y Biomedicina "Lopez-Neyra". Consejo Superior de Investigaciones Cientificas, Armilla, Granada, Spain.
J Enzyme Inhib Med Chem. 2009 Feb;24(1):111-6. doi: 10.1080/14756360801915476.
The enzyme deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) catalyses the hydrolysis of dUTP to dUMP and PPi thus controlling the incorporation of uracil into DNA genomes. In Campylobacter jejuni dUTPase exhibits structural properties of dimeric proteins characteristic of protozoa of the Kinetoplastidae family. In the present study we perform a kinetic analysis of Campylobacter dUTPase using the continuous spectrophotometric method and show that the enzyme is highly specific for deoxyuridine nucleotides. The Michaelis-Menten constant for dUTP was 0.66 microM while the k(cat) was 12.3 s(- 1). dUDP was also efficiently hydrolysed although the specificity constant, k(cat)/K(m), was five fold lower than for dUTP. The reaction product and the non hydrolysable analogue alpha,beta imido dUDP are potent inhibitors of the enzyme while several analogues of dUMP with substituents at the 3'- and 5'-positions active against trimeric dUTPases, show poor inhibitory activity. Apparent structural and kinetic differences with other eukaryotic dUTPases suggest that the present enzyme might be exploited as a target for new drugs against campylobacteriosis.
脱氧尿苷5'-三磷酸核苷酸水解酶（dUTPase）催化dUTP水解为dUMP和焦磷酸（PPi），从而控制尿嘧啶掺入DNA基因组。空肠弯曲菌中的dUTPase表现出与动质体科原生动物特征性二聚体蛋白相似的结构特性。在本研究中，我们使用连续分光光度法对弯曲菌dUTPase进行了动力学分析，结果表明该酶对脱氧尿苷核苷酸具有高度特异性。dUTP的米氏常数为0.66微摩尔，而催化常数（k(cat)）为12.3秒-1。dUDP也能被有效水解，尽管其特异性常数k(cat)/K(m)比dUTP低五倍。反应产物和不可水解类似物α,β-亚氨基dUDP是该酶的有效抑制剂，而几种在3'-和5'-位带有取代基的dUMP类似物对三聚体dUTPases有活性，但抑制活性较差。与其他真核生物dUTPases明显的结构和动力学差异表明，该酶可能被用作开发抗弯曲菌病新药的靶点。
