Phosphorus nuclear magnetic resonance studies of the pyrophosphate backbone of pyridine coenzymes

Phosphorus nuclear magnetic resonance spectra of pyridine coenzymes show that the reduced and the oxidized coenzymes exhibit different spectral patterns and chemical shifts. The 31 P{ 1 H} NMR spectrum of β‐TPN taken as a function pH indicates that the pKa value for the 2′ phosphate group is 6·0. It was further found that in β‐TPN, the protonation of the 2′ phosphate group selectively perturbs one 31 P resonance of the pyrophosphate backbone.