Calcium is sufficient but not necessary for activation of sheep platelet cytosolic phospholipase A2

In this study we demonstrate that: (1) although the major phospholipase A2 present in sheep platelets is activated by calcium ions, it can effectively catalyze hydrolysis of the sn‐2 ester linkage in phospholipids in the absence of calcium: (2) expression of calcium‐independent phospholipase A2 acti...

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Bibliographic Details
Published in:FEBS letters 1991-06, Vol.284 (1), p.27-30
Main Authors: Zupan, Lori A., Kruszka, Kelly K., Gross, Richard W.
Format: Article
Language:English
Subjects:
Analytical, structural and metabolic biochemistry
Animals
Arachidonic acid
Biological and medical sciences
Blood Platelets - enzymology
Calcium
Calcium - pharmacology
Chromatography, Gel
Enzyme Activation
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
Hydrolases
Phospholipase A2
Phospholipases A - blood
Phospholipases A2
Phospholipids - metabolism
Plasmalogen
Platelet
Sheep
Sodium Chloride - pharmacology
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Summary:In this study we demonstrate that: (1) although the major phospholipase A2 present in sheep platelets is activated by calcium ions, it can effectively catalyze hydrolysis of the sn‐2 ester linkage in phospholipids in the absence of calcium: (2) expression of calcium‐independent phospholipase A2 activity can be induced by NACl utilizing purified (but not crude) cytosolic enzyme; and (3) calcium‐independent phospholipase A2 activity is regulated by a reconstitutable cytosolic protein. Collectively, these results underscore the fundamental catalytic differences between extracellular and intracellular calcium‐dependent phospholipases A2 and demonstrate that calcium is sufficient, but not necessary, for the activation of this class of intracellular phospholipases A2
ISSN:0014-5793
1873-3468
DOI:10.1016/0014-5793(91)80753-P