ABSORPTION SPECTRA OF DEOXYRIBOSE, RIBOSEPHOSPHATE, ATP AND DNA BY DIRECT TRANSMISSION MEASUREMENTS IN THE VACUUM‐UV (150—190 nm) AND FAR‐UV (190—260 nm) REGIONS USING SYNCHROTRON RADIATION AS A LIGHT SOURCE

Transmission measurements of 2‐deoxy‐D‐ribose, D‐ribose‐5‐phosphate, ATP and DNA at 5 nm intervals were made with thin films in the wavelength region between 150 nm and 260 nm using synchrotron radiation. ATP and DNA exhibited two peaks in the absorption spectra around 260 nm and 190 nm, and a steep increase below 170 nm, while ribose phosphate and deoxyribose only exhibited the increase below 190 nm with no appreciable absorption above 190 nm. Since adenine does not exhibit the increase of absorption below 180 nm, these results indicate that the absorption of the sugar‐phosphate group, rather than adenine, contributed to the increase below 170 nm in the absorption spectra of ATP and DNA.