Nucleotides and derived compounds were analyzed by reversed
phase-HPLC with an 1100 Agilent liquid chromatograph (Agilent
Tech., CA, USA) equipped with a diode array detector. The chromatographic
separation was performed as described above. The separated
compounds were monitored using a diode array detector at a wavelength
of 260 nm for ATP, AMP, UMP, GMP and NADH and 250 nm for
IMP, inosine and hypoxanthine. Uric acid was detected at 280 nm. The
separated compounds were identified by their respective retention
times and spectrum between 200 and 350 nm. Quantification was performed
by means of their respective calibration curves