[Characterization of Ca-uptake by a microsomal fraction from vascular smooth muscle].
A microsomal fraction was isolated from the media-intima of the bovine carotid artery; the preparation is a mixed fraction of membranal and mitochondrial debris, which is able to bind Ca-ions and to take them up in the presence of ATP. The Ca-uptake is activated within a pCa range from 7--5. The involvement of two different systems in the Ca-uptake is discussed. A Ca-stimulatable ATPase was demonstrated, whose relationship with a Ca-transport system could not be established, however. The substrate for Ca-uptake is MgATP; in addition, free Mg has a stimulating effect. The Na/Kratio has no influence on the Ca-uptake. The influence of the pH-value on the Ca-binding and Ca-uptake was studied. Phosphate increased the Ca-uptake, while oxalate did not. The investigated system is discussed as a model for the action of vaso-active drugs.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002339:Carotid Arteries / Q000378:metabolism*; D002417:Cattle; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008861:Microsomes / Q000378:metabolism* / Q000648:ultrastructure
D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium
Zur Charakterisierung der Ca-Aufnahme durch eine Mikrosomenfraktion aus glatter Gefässmuskulatur.