Fig. 5

¹³CO₂ contributes to adenosine biosynthesis. A Schematic of adenosine biosynthesis from various carbon sources. B ¹³C labeling pattern of adenosine from sarcoma cells fed with [U-¹³C]-glutamine/[U-¹³C]-glucose in vitro for 3 h and labeling patterns of adenosine in sarcomas from sarcoma-bearing mice receiving [U-¹³C]-glutamine/[U-¹³C]-glucose infusion in vivo for 3 h. Data are presented as mean ± SD n = 5 for animals and n = 3 for cultured cells. R5P, ribose 5-phosphate; AIR, aminoimidazole ribotide; CAIR, 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate. Data in this figure was after natural abundance correction