Structure, function and subcellular localization of a human platelet Ca2+-ATPase
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Updated: Aug 14, 2026

Measuring In Vitro ATPase Activity for Enzymatic Characterization
Published on: August 23, 2016
1Department of Biochemistry, University of Louisville, Kentucky.
Abstract:
Human platelets contain a Ca2+-ATPase in internal membranes that is essential for Ca2+ homeostasis. This Ca2+ pump has enzymatic properties quite similar to the sarcoplasmic reticulum (SR) Ca2+ pumps. Antibodies against the SR Ca2+ pump crossreact with the human platelet protein. However, the platelet Ca2+-ATPase is approximately 10 kD larger than the SR pumps and exhibits a larger mRNA coding for the protein in a megakaryocyte tumor cell line. In addition, the platelet Ca2+-pump may be localized in specialized internal membrane structures that function in Ca2+ uptake and release. These results suggest that the platelet Ca2+-ATPase may represent a new class of internal membrane Ca2+-pumps.
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