Cleavage of Adenosine by Human Red Cells

IN thc last ycar it has bccomc clear that nuclcosides can form a substrate for the mctabolism of the human rcd ccll. Dischc (1951) had shown this previously with red-cell haemolysates. Fiiich and Gabrio (1954) have shown that storage of cells with adenosine increases their survival tiiiic after transfusion and Prankerd and Altmaii (1954) showed that incubation of human red cells with 32P-orthophosphate and adenosine after exhaustion of all glucose leads to incorporation of the labelled phosphate into phosphate esters within the cell, and that adciiosiiic cffccts this changc even after prolonged incubation when glucose no longer does. Prankerd and Altmaii, looking for an cxplanation of this phenomenon, suggested that the rcd ccll contains a iiuclcosidc phosphorylase, which splits adenosine and that the phosphorylatcd pciitose moiety is then metabolized. They produced indirect evidence in favour of this hypothesis. T h e present cxpcrimeiits were designed to answer the following questions:I. If adenosine is cleaved by red-ccll enzymes, is the purine fraction utilized by the rcd cell or lcft in thc cxtracellular fluid? (It has bcen suggested that it may contribute to intracellular adcnosiiic triphosphate (ATP) ) . 2 . Will thc red ccll preferentially utilizc one substrate for another when both glucose and adciiosiiic arc included in the incubating system? 3. What is tlic ratc of adeiiosiiic consumption by fresh red cells during incubation?