C-13-NMR Measurement of Pyrroloquinoline Quinone in Deuterium Oxide Using Cryo-probe and Spectral Identification by the Quantum Chemical Calculation

摘要

Coenzyme pyrroloquinoline quinone (PQQ) is an important molecule in biology, chemistry and engineering. It has 14 kinds of carbon atoms, and there are 14 peaks in DMSO-d6 on the C-13-NMR measurement. The disodium salt of PQQ (Na(2)PQQ), used as food, is not dissolved in DMSO. A C-13-NMR assignment of Na(2)PQQ in deuterium oxide has not been reported. As for the measurement with a high sensitivity detector (cryo detector), 28 peaks could be observed in deuterium oxide. A quantum chemical calculation revealed that it has two states in equilibrium with the acetal structure by the addition of water to the quinone moiety.