Ca2(+)-driven [3H]arachidonate release in electropermeabilized human platelets shows an absolute requirement for MgATP2-.
Addition of micromolar Ca2+ to electropermeabilized human platelets which had been pre-labelled with [3H]arachidonate causes release of 3H only when millimolar concentrations of a nucleoside triphosphate, e.g. ATP, are present in the incubation medium. Addition of millimolar Ca2+ in the absence of ATP, or preincubation with ATP before addition of micromolar Ca2+, fails to cause a significant increase in 3H release. Purine nucleotides are more effective than pyrimidine nucleotides in activating Ca2(+)-driven 3H release. This activation does not appear to involve phosphate transfer, since metabolically stable analogues of ATP, e.g. the beta gamma-imido analogue, are effective in promoting 3H release.
Patel
S
S
Division of Biomolecular Sciences, King's College, London, U.K.
Scrutton
M C
MC
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002463:Cell Membrane Permeability; D004558:Electric Stimulation; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D010743:Phospholipids / Q000097:blood*; D012265:Ribonucleotides / Q000494:pharmacology; D014316:Tritium
D001095:Arachidonic Acids; D010743:Phospholipids; D012265:Ribonucleotides; D014316:Tritium; D016718:Arachidonic Acid; D000255:Adenosine Triphosphate; D002118:Calcium