Bacterial Synthesis of Nucleotides

Part I. Nucleoside Phosphotransferase of Escherichia coli

Abstract

The nucleoside phosphotransferase of Escherichia coli was partially purified by the ammonium sulfate fractionation and acid precipitation and confirmed to synthesize mainly 3'(& 2')-inosinic acid together with a small amount of 5'-isomer from inosine and p-nitrophenylphosphate.
The optimum pH of this reaction was found to be at the pH of around 5.0.
The efficiency of this phosphate transfer reaction is the functions of the kind of phosphate donor and of the concentration of acceptor and donor. p-Nitrophenylphosphate was the most excellent donor for this reaction.
From the results of experiments using inhibitors or metallic ions, it appeared that cupric ion and zinc ion affected on the nucleoside phosphotransferase, especially the former accelerated both IMP synthesis and liberation of p-NP, and it was discussed that the nucleoside phosphotransferase may be differnet from the phosphatase.