Identification of plasmalogen as the major phospholipid constituent of cardiac sarcoplasmic reticulum.
The phospholipid molecular species of canine myocardial sarcoplasmic reticulum were identified by fast atom bombardment mass spectrometry, reverse-phase high-performance liquid chromatography, and other conventional techniques. Cardiac sarcoplasmic reticulum contains 1.4 mumol of lipid Pi/mg of protein which is comprised of 53% plasmalogen. Cardiac sarcoplasmic reticulum ethanolamine glycerophospholipid contains 73% plasmalogen that is predominantly comprised of moieties with 18-carbon vinyl ethers at the sn-1 position and arachidonic acid at the sn-2 position. In contrast, canine skeletal muscle sarcoplasmic reticulum contains only 19% plasmalogen that is predominantly comprised of ethanolamine plasmalogen (78% of skeletal muscle sarcoplasmic reticulum ethanolamine glycerophospholipid) with arachidonic and docosatetraenoic acids at the sn-2 position. The possibility that tetraenoic ethanolamine plasmalogens in both cardiac and skeletal muscle sarcoplasmic reticulum facilitate calcium translocation by their propensity for adopting a hexagonal II conformation at physiologic temperatures is discussed.
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D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004285:Dogs; D004987:Ethers / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D008929:Mitochondria, Heart / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D010955:Plasmalogens / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D014753:Vinyl Compounds
D004987:Ethers; D005227:Fatty Acids; D010743:Phospholipids; D010955:Plasmalogens; D014753:Vinyl Compounds; C100195:vinyl ether; D000252:Calcium-Transporting ATPases; D002118:Calcium