Restoration of malonyl-CoA sensitivity of soluble rat liver mitochondria carnitine palmitoyltransferase by reconstitution with a partially purified malonyl-CoA binding protein.
Solubilization of rat liver mitochondria in 5% Triton X-100 followed by chromatography on a hydroxylapatite column resulted in the identification of malonyl-CoA binding protein(s) distinct from a major carnitine palmitoyltransferase activity peak. Further purification of the malonyl-CoA binding protein(s) on an acyl-CoA affinity column followed by sodium dodecyl sulfate gel electrophoresis indicated proteins with Mr mass of 90 and 45-33 kDa. A purified liver malonyl-CoA binding fraction, which was devoid of carnitine palmitoyltransferase, and a soluble malonyl-CoA-insensitive carnitine palmitoyltransferase were reconstituted by dialysis in a liposome system. The enzyme activity in the reconstituted system was decreased by 50% in the presence of 100 microM malonyl-CoA. Rat liver mitochondria carnitine palmitoyltransferase may be composed of an easily dissociable catalytic unit and a malonyl-CoA sensitivity conferring regulatory component.
Woldegiorgis
G
G
Department of Medicine, University of Wisconsin-Madison 53706.
Fibich
B
B
Contreras
L
L
Shrago
E
E
D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D008316:Malonyl Coenzyme A / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000201:enzymology*; D051381:Rats
D008565:Membrane Proteins; D008316:Malonyl Coenzyme A; D002334:Carnitine O-Palmitoyltransferase