Stimulation of phospholipase A2 activity in mitochondria by magnesium and polyamines.
Endogenous phospholipase A2 activity in hypotonically swollen, non-respiring rat liver mitochondria was found to be stimulated by 1-10 mM magnesium and by 0.5-1.2 mM of the polyamines spermine and spermidine in the absence of added calcium. This was interpreted as being due to effects of these cations on the physicochemical properties of membrane phospholipids. The activity in the presence of 0.2 mM calcium was inhibited by 0.2 mM strontium. The calcium-stimulated activities were stimulated more than twofold in hypotonically (50 mOsm/litre) swollen mitochondria in comparison with non-swollen mitochondria.
Saris
N E
NE
Department of Medical Chemistry, University of Helsinki, Finland.
D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D004789:Enzyme Activation; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008930:Mitochondria, Liver / Q000201:enzymology*; D010741:Phospholipases A / Q000187:drug effects / Q000378:metabolism*; D054467:Phospholipases A2; D051381:Rats; D013095:Spermidine / Q000494:pharmacology*; D013096:Spermine / Q000494:pharmacology*
D002413:Cations, Divalent; D013096:Spermine; D010741:Phospholipases A; D054467:Phospholipases A2; D008274:Magnesium; D013095:Spermidine