Xanthosine metabolism in plants: Metabolic fate of exogenously supplied 14C-labelled xanthosine and xanthine in intact mungbean seedlings

► The metabolic fate of 14C-xanthosine and 14C-xanthine was studied in intact mungbean seedlings. ► Exogenously supplied xanthosine and xanthine were degraded mainly via allantoin. ► Salvage of xanthosine and xanthine for nucleotide and RNA synthesis was tiny. ► Allopurinol severely inhibited catabolism of xanthine, but did not stimulate xanthine salvage.