Effect of long-term phosphate starvation on the levels and metabolism of purine nucleotides in suspension-cultured Catharanthus roseus cells.
The effect of long-term phosphate (Pi) starvation of up to 3 weeks on the levels of purine nucleotides and related compounds was examined using suspension-cultured Catharanthus roseus cells. Levels of adenine and guanine nucleotides, especially ATP and GTP, were markedly reduced during Pi-starvation. There was an increase in the activity of RNase, DNase, 5'- and 3'-nucleotidases and acid phosphatase, which may participate in the hydrolysis of nucleic acids and nucleotides. Accumulation of adenosine, adenine, guanosine and guanine was observed during the long-term Pi starvation. Long-term Pi starvation markedly depressed the flux of transport of exogenously supplied [8-(14)C]adenosine and [8-(14)C]adenine, but these labelled compounds which were taken up by the cells were readily converted to adenine nucleotides even in Pi-starved cells, in which RNA synthesis from these precursors was significantly reduced. The activities of adenosine kinase, adenine phosphoribosyltransferase and adenosine nucleosidase were maintained at a high level in long-term Pi starved cells.
Shimano
Fusako
F
Department of Molecular Biology and Biochemistry, Graduate Division of Life Sciences, Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, Japan.
Ashihara
Hiroshi
H
D000227:Adenine Nucleotides / Q000737:chemistry / Q000378:metabolism; D000228:Adenine Phosphoribosyltransferase / Q000378:metabolism; D000248:Adenosine Kinase / Q000378:metabolism; D030008:Catharanthus / Q000166:cytology* / Q000378:metabolism*; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D006150:Guanine Nucleotides / Q000737:chemistry / Q000378:metabolism; D006867:Hydrolases / Q000378:metabolism; D009699:N-Glycosyl Hydrolases / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010710:Phosphates / Q000378:metabolism*; D011685:Purine Nucleotides / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis
D000227:Adenine Nucleotides; D006150:Guanine Nucleotides; D010710:Phosphates; D011685:Purine Nucleotides; D012313:RNA; D000228:Adenine Phosphoribosyltransferase; D000248:Adenosine Kinase; D006867:Hydrolases; D009699:N-Glycosyl Hydrolases; C019599:adenosine nucleosidase