Phospholipids activate cathepsin D.
Total lipids as well as phospholipids extracted from the mitochondrial-lysosomal fraction of porcine adrenal cortex activated the lysosomal cathepsin D of this tissue 30- and 40-fold, respectively, with bovine serum albumin as the substrate. Phosphatidic acid, phosphatidyl ethanolamine, phosphatidyl serine, phosphatidyl inositol, phosphatidyl glycerol and cardiolipin were found to activate greatly the cathepsin D. The degree of activation ranged from 6-fold by phosphatidyl ethanolamine to 40-fold by cardiolipin at 1 mM, respectively. These results strongly point to the importance of phospholipids in intracellular protein degradation by lysosomal cathepsin D.
D000302:Adrenal Cortex / Q000201:enzymology* / Q000502:physiology; D000818:Animals; D002402:Cathepsin D; D002403:Cathepsins / Q000378:metabolism*; D004789:Enzyme Activation; D007700:Kinetics; D008055:Lipids / Q000494:pharmacology; D008247:Lysosomes / Q000502:physiology; D008928:Mitochondria / Q000502:physiology; D010743:Phospholipids / Q000302:isolation & purification / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013552:Swine
D008055:Lipids; D010743:Phospholipids; D002403:Cathepsins; D002402:Cathepsin D