title: Ca++-binding properties of cznine aortic microsomes: lack of effect of c-AMP.
abstract: Ca++-binding to a microsomal fraction canine aorta has been studied and compared to Ca++-binding to canine cardiac microsomes. The aortic microsomes bound up to 60 nmoles Ca++/mg protein with a first-order binding rate constant of 0.025 sec-1. The binding rate of 5 sec was about half that of cardiac microsomes, 8 versus 15 nmoles/mg. The Ca++-binding to the aortic microsomes had a pH optimum of 7.4, was inhibited by monovalent cations and showed ATP preference when compared to other nucleotides. The binding was not stimulated by the presence of oxalate. c-AMP stimulated incorporation of 32P into the preparation, but had no effect on Ca++-binding.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology*; D004285:Dogs; D008861:Microsomes / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D013053:Spectrophotometry
chemical_list: D010758:Phosphorus; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D000251:Adenosine Triphosphatases; D002118:Calcium