Abstract
It was found that CDP-choline was formed with good yield from 5′-CMP and choline phosphate or choline chloride by yeast cells. The effects of pyrophosphate (PPi) on the formation of UDPG, GDPM and CDP-choline from respective nucleoside monophosphate by yeast cells were studied. By the addition of PPi to the reaction mixture, the phosphorylation of G-6-P from glucose was inhibited and then the phosphorylation of nucleoside monophosphates was restrained. Such inhibition was reversed by the decomposition of PPi by inorganic pyrophosphatase of yeast cells. The addition of PPi after the formation of nucleotide derivatives caused the accumulation of UTP and GTP and molar yields from nucleotide as substrate was about 80%. But that of CTP was a little in the reaction system of CDP-choline synthesis. Further, this method seems to be suitable for the accumulation of sugar-1-phosphates.