Fig. 4
1H-NMR spectra ranging chemical shift of 2.0–4.0 ppm and structures of (a) 5S-DHdThd (Product 1), (b) 5S-DDdThd (Product 1′), (c) 5R-DHdThd (Product 2), and (d) 5R-DDdThd (Product 2′). (e) pD dependence of Da/Db values on addition of a deuterium atom to the 6 position of dThd when a 99.9% D2O solution of 3 mM dThd, 7 mM α-TP, and 100 mM potassium phosphate buffer at pD 5.9–12.5 was irradiated with UV light at 37°C for 60 min. 5S-DDdThd (Product 1′) (closed circles) and 5R-DDdThd (Product 2′) (open circles). The Da/Db values were calculated from integral values of H-6a and H-6b signals of 1H NMR