title: Ca2+ dependency of diadenosine 5',5"'-p1,p4-tetraphosphate degradation in dog plasma.
abstract: Diadenosine 5',5"'-p1,p4-tetraphosphate (Ap4A) degradation in dog plasma was inhibited by the addition of EDTA. The Ap4A degrading activity seemed to be recovered by the addition of metal ions, Ca2+, Co2+, Cu2+, Mg2+, Mn2+ or Zn2+ to plasma in which the activity was lost by the addition of EDTA. Especially, the degradation was accelerated by the addition of Ca2+ to the plasma, and the degradation rate was dependent on the concentration of Ca2+. The results of this study suggested that the enzymatic degradation of Ap4A in dog plasma was modulated by the concentration of Ca2+.
mesh_terms: D000328:Adult; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D015226:Dinucleoside Phosphates / Q000097:blood* / Q000493:pharmacokinetics; D004285:Dogs; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D006207:Half-Life; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008670:Metals / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015290:Second Messenger Systems / Q000187:drug effects*
chemical_list: D015226:Dinucleoside Phosphates; D008670:Metals; C020733:diadenosine tetraphosphate; D004492:Edetic Acid; D002118:Calcium