High resolution 31P nuclear magnetic resonance spectra at 145.7 MHz are reported for intact Ehrlich ascites tumor cells and their perchloric acid extracts. In the extracts it was possible to assign resonances to fructose 1,6 bisphosphates, dihydroxyacetone phosphate, ATP, ADP, AMP, Pi, NAD+ phosphorylcholine, glycero 3 phosphorylcholine, glycero 3 phosphorylethanolamine, and glyceraldehyde 3 phosphate from their chemical shifts, pH behavior and spin couplings. All but glyceraldehyde 3 phosphate were observed and assigned in the intact cells. It was possible to show that the hydrolysis of fructose 1,6 bisphosphate to dihydroxyacetone phosphate and glyceraldehyde 3 phosphate is in equilibrium, that the dihydroxyacetone phosphate → glyceraldehyde 3 phosphate reaction is not, and that in the intact cell without added oxygen or glucose the reaction 2ADP ⇆ ATP + AMP is in equilibrium. From the known pH dependence of the Pi resonance it was possible to show that during aerobic or anerobic glycolysis the difference between intracellular and extracellular pH values was <0.2 pH units. Upon oxygenation the ATP concentration increased while the ADP concentration fell. Introducing deoxyglucose depleted the ATP and resulted in an AMP signal and one from deoxyglucose 6 phosphate, which is transported and phosphorylated but not catabolized.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - 1977