Regulation of NAD and NADP synthesis in human red cell.
NAD is synthesized in red cell from nicotinic acid and PRPP through the formation of nicotinate mononucleotide and desamido-NAD. Synthesis of one mole of NAD requires two moles of ATP. NADP comes from NAD phosphorylation by NAD-kinase (EC.2.7.1.23). NAD and NADP analysis on a population with ATP level ranging from 800 to 2500 nmoles/ml red cells showed a close correlation between ATP and pyridine cofactors. Moreover, NADP level appeared to be dependent of the redox-state of NADP/NADPH couple. Subjects with low NADPH (G-6-PD) deficient red cells, Hb Köln) showed lower NADtot/NADPtot ratio, suggesting a NAD-kinase equilibrium shift toward NADP related to lower levels of the negative effector NADPH, as already described in rat liver.
Regulation of NAD and NADP synthesis in human red cell. NAD is synthesized in red cell from nicotinic acid and PRPP through the formation of nicotinate mononucleotide and desamido-NAD. Synthesis of one mole of NAD requires two moles of ATP. NADP comes from NAD phosphorylation by NAD-kinase (EC.2.7.1.23). NAD and NADP analysis on a population with ATP level ranging from 800 to 2500 nmoles/ml red cells showed a close correlation between ATP and pyridine cofactors. Moreover, NADP level appeared to be dependent of the redox-state of NADP/NADPH couple. Subjects with low NADPH (G-6-PD) deficient red cells, Hb Köln) showed lower NADtot/NADPtot ratio, suggesting a NAD-kinase equilibrium shift toward NADP related to lower levels of the negative effector NADPH, as already described in rat liver.