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Time‐resolved resonance Raman, time‐resolved UV–visible absorption and DFT calculation study on photo‐oxidation of the reduced form of nicotinamide adenine dinucleotide
Author(s) -
Takahashi Noriko,
Shinno Takaaki,
Tachikawa Masanori,
Yuzawa Tetsuro,
Takahashi Hiroaki
Publication year - 2006
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1472
Subject(s) - chemistry , photochemistry , protonation , raman spectroscopy , absorption (acoustics) , nicotinamide adenine dinucleotide , absorption band , radical ion , deprotonation , resonance (particle physics) , nad+ kinase , moiety , ion , stereochemistry , materials science , organic chemistry , atomic physics , optics , composite material , enzyme , physics
Photochemical reaction of the reduced form of nicotinamide adenine dinucleotide (NADH) was studied in aqueous solutions using nanosecond time‐resolved resonance Raman and UV–visible absorption spectroscopies combined with DFT/B3LYP calculations. Four transients were detected. A transient exhibiting absorption bands at 370 and 560 nm was assigned to the cation radical NADH +• . A transient having an absorption band at 394 nm was assigned to the deprotonated neutral radical NAD • . A transient exhibiting an absorption band at 493 nm was considered to be attributable to the anion radical NADH −• . The broad and strong band at about 700 nm was assigned to hydrated electrons. It was concluded that the photo‐oxidation of NADH to NAD + proceeded stepwise via NADH +• and NAD • . The Raman band at 1627 cm −1 of NADH +• was assigned to the CC symmetric stretch of the protonated pyridyl ring of the dihydronicotinamide moiety. It was shown that the CC symmetric stretch of the protonated pyridyl ring exhibited a low‐wavenumber shift from 1688 cm −1 to 1627 cm −1 on going from the ground state to NADH +• . This implies that the protonated pyridyl ring is weakened considerably on ionization in good accord with the DFT calculations. Copyright © 2006 John Wiley & Sons, Ltd.