Comparison of Purine Metabolism in Suspension Cultured Cells of Different Growth Phases and Stem Tissue of Catharanthus roseus

The overall metabolism o f [8-l4C]adenine, [8-14C]adenosine, [8-l4C]guanine, [8-14C]hypoxanthine and [8-14C]inosine in suspension cultured cells o f the lag, cell division, cell expansion and stationary phases and stem tissue o f Catharanthus roseus was studied. On a fresh weight basis, absorption o f all purine bases and nucleotides by the cultured cells was 10 —400 times higher than that by the stem tissue. The conventional pathways o f purine salvage and degradation were operative both in the cultured cells and stem tissue. [8-14C]Adenine and [8-14C]adenosine were extensively salvaged to nucleotides and nucleic acids in both the cultured cells and the stem tissue. [8-l4C]-Guanine, [8-l4C]hypoxanthine and [8-14C]inosine were incorporated into either salvage products (nucleotides and nucleic acids) or degradation products (C 0 2, allantoin and allantoic acid) o f cultured cells and stem tissue. The highest incorporation rate expressed as a percentage o f absorbed 14C into the degradation products was observed in the lag phase (12h-old) cultured cells. Incorporation o f all precursors into nucleotides and bases was much higher in the stem tissue than in the culltured cells.