Kinetic studies on the reaction catalyzed by polynucleotide kinase from phage T4-infected Escherichia coli

Abstract

Kinetic properties of polynucleotide kinase (EC 2.7.1.78) isolated from Escherichia coli cells infected with phage T4 were investigated. The reaction depends on the concentration of MgATP, while free ATP or free Mg2+ have neither inhibitory nor accelerating effect. The initial reaction velocity was plotted against variable concentrations of ATP as the phosphate donor at various fixed concentrations of 5'-hydroxyl-DNA or -oligo(rA) as the phosphate acceptor in the presence or absence of products. The double reciprocal plot analysis of the data suggested that the reaction obeys the random sequential mechanism. Various constants were determined and the reaction mechanism was discussed.