Studies on the metabolism of adenosine and adenine in stored and fresh human erythrocytes.

By BERTRAM A. Lowi’ AND MARJORIE K. WILLIAMS T HE MATURE human erythrocyte, which is incapable of de novo purine nucleotide synthesis, can utilize preformed purines and purine nucleosides for tile formation of purine nucleotides, in vitro.” 2 Studies in this laboratory have demonstrated that adenine is an effective precursor of the ATP of the human erythrocyte and that hypoxanthine, guanine, and xanthine lead to tile formation of GTP.’ Tile aglycones of the purine nucleosides, inosine and guanosine, serve as precursors of GTP after being formed by phosphorylytic cleavage of the rihosyh compounds by the purine nt,cleoside phosphorylase of the erythrocyte.’ The failure of hypoxanthine and inosine to serve as precursors of the ATP in tile human erytilrocyte, although they are efficiently utilized for IMP formation, has served to demonstrate a difference in a metabolic capacity of rabbit and human erythrocytes. This difference has been localized as a failure of the human cell to convert inosine 5’-phosphate to AMP.’ Tile metabolism of adenosine has also been investigated and its extensive conversion to IMP has been demonstrated, a metabolic fate that is compatible with tile known rapid rate of deamination of adenosine to inosine in the human erythrocyte.”3 Several reports have indicated that the presence of adenosine in blood storage media leads to an increased concentration of ATP and to an enhanced post-transfusion survival in stored cells. ’’ Overgaard-Hansen et al. have