P. Reichard
Nov 1, 1962
Citations
1
Influential Citations
87
Citations
Quality indicators
Journal
The Journal of biological chemistry
Abstract
Extracts from Escherichiu coli catalyze the formation of deoxycyticlme phosphates from cytidine 5’-phosphate (1). Optimal formation of deoxynucleotides required the addition of adenosine triphosphate and Mg* ions to the extract, and, after treatment with Dowex 2, a strong stimulation of the reaction by reduced triphosphopyridine nucleotide was observed. Similar results were obtained in extracts from Novikoff hepatoma (2), from chick embryo (3), and from different mammalian tissues (4). In the latter case, a requirement for DPNH (in place of TPNH) was reported. Evidence was obtained with the enzyme system from Escherichia coli that dCDP was the primary product of the reaction, and it was suggested that the reduction of the rihonucleotide to the deoxyribonucleotide occurred at the diphosphate level. Recently we reported briefly results obtained with partially purified enzyme fractions from Escherichia coZi (5). The formation of deoxycytidine phosphates from CMP required the participation of two protein fractions. One was shown to catalyze the phosphorylation of CMP to CDP, whereas the other fraction catalyzed the reduction of the ribonucleoside diphosphate to dCDP. This latter reaction required the addition of .1TP, Mg++ ions, and reduced lipoic acid. TPNH was not active with the purified preparation. The present paper is a full report of these studies.