Fig. 5.
Schematic diagram showing the primary importance of NADPH sources and secondary importance of NADPH sinks on the 2H-composition of NAPDH and lipid/water 2H-fractionation (2εlipid/water). The size of the gray box indicates the magnitude of change. Other tertiary sources include exchange of hydrogen atoms on NADPH with that in water and metabolites (SI Appendix, SI Discussions 1 and 4). IDH, isocitrate dehydrogenase; G6PDH, glucose-6-phosphate dehydrogenase, and 6PGDH, 6-phosphogluconate dehydrogenase in the oxPPP.