Carnitine palmityltransferase activity during myocardial ischemmia and at low ionic strengths.
Carnitine palmityltransferase activity was measured in mitochondria isolated from control and ischemic dog heart. The ischemic activity demonstrated a decrease in both the Vmax and the Km of the enzyme for 1-carnitine when measured in the presence of 160 muM palmityl-CoA. The kinetic response of the mitochondrial carnitine palmityltransferase to ischemia was mimicked by assay of the enzyme from control mitochondria in a medium of low ionic strength. The effect of ionic strength on enzyme activity was directly correlated with binding of palmityl-CoA to the mitochondrial membranes. The decrease in carnitine palmityltransferase activity in ischemic mitochondria may reflect a decrease in palmityl-CoA binding to the enzyme active site. The depression in ischemic carnitine palmityltransferase activity may represent an early defect in mitochondrial metabolism.
D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism*; D003065:Coenzyme A / Q000378:metabolism; D003327:Coronary Disease / Q000201:enzymology*; D004285:Dogs; D007700:Kinetics; D008931:Mitochondria, Muscle / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology*; D009994:Osmolar Concentration; D010169:Palmitic Acids / Q000378:metabolism; D016276:Ventricular Function
D010169:Palmitic Acids; D000217:Acyltransferases; D002334:Carnitine O-Palmitoyltransferase; D003065:Coenzyme A