Figure 9.

Electronic absorption spectra of three ribosides of 1,N⁶-etheno-isoguanine, purified by HPLC. Spectra of N9- (red color) and N7-β-d-riboside (blue) were measured in 50 mM phosphate buffer, pH 6.5, and that of N⁶-riboside (yellow), at pH 7.