Incorporation of [32P]orthophosphate into inorganic polyphosphates by human granulocytes and other human cell types.
When human peripheral blood granulocytes were metabolically labeled at 37 degrees C with [32P]orthophosphate, inorganic polyphosphates became preferentially radiolabeled. Incorporation of radiolabel into the polymer appeared to be ATP-independent. [32P]Polyphosphate was identified by its (i) characteristic lability to acid hydrolysis, (ii) insolubility in barium acetate (pH 4.5), (iii) conversion to [32P]trimetaphosphate, (iv) hydrolysis to [32P]orthophosphate by an exopolyphosphate (Saccharomyces cerevisiae scPPX1), and (v) conversion to a "phosphate ladder" which co-migrated on a polyacrylamide gel with a synthetic phosphate ladder. Also, indirect evidence suggested that the [32P]polyphosphate was strongly, noncovalently associated with another unknown molecule. Particulate fractions (13,000 x g) from lysates of human granulocytes, skin fibroblasts, HL-60 and SK-N-SH cells, all demonstrated radiolabeling of polyphosphate when incubated at 37 degrees C with [32P]orthophosphate.
Cowling
R T
RT
Ottawa Regional Cancer Centre, Ontario, Canada.
Birnboim
H C
HC
D017766:Acid Anhydride Hydrolases / Q000378:metabolism; D001345:Autoradiography; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line; D005347:Fibroblasts / Q000378:metabolism; D006098:Granulocytes / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D015473:Leukemia, Promyelocytic, Acute; D010710:Phosphates / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D011122:Polyphosphates / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D012867:Skin / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D010710:Phosphates; D010761:Phosphorus Radioisotopes; D011122:Polyphosphates; D017766:Acid Anhydride Hydrolases; C020137:exopolyphosphatase; D002118:Calcium