Metabolic Fate of Inorganic Phosphate Absorbed by Suspension Cultured Cells of Catharanthus roseus.

The absorption and metabolism of [(32)P]inorganic phosphate (Pi) by suspension cultured cells of Catharanthus roseus was studied. The cells absorbed 46 % of the Pi from fresh medium during the first day after inoculation. More than 90% of the Pi had been absorbed by the end of the culture period (10 days). Free Pi in the cells decreased with growth and more than 85% of the absorbed [(32)P]Pi was found as organic phosphates at the stationary phase. A large proportion of the absorbed Pi was incorporated into nucleic acids (45%) and phospholipids (30%), 5-10% into nucleotides and less than 3 % into sugar phosphates and proteins.