xanthine + formaldehyde + NADP(+) + H2O => 7-methylxanthine + NADPH + O2 + H(+)
xanthine + formaldehyde + nadp(+) + h2o => 7-methylxanthine + nadph + o2 + h(+)
xanthine + formaldehyde + NADP(+) + H2O => 7-methylxanthine + NADPH + O2 + H(+)
xanthine + formaldehyde + nadp(+) + h2o => 7-methylxanthine + nadph + o2 + h(+)