ACETOACETATE ACTIVATION AND OXIDATION IN KIDNEY AND HEART MITOCHONDRIA

The conditions under which acetoacetate is oxidized by kidney and heart mitochondria have been studied. By means of specific inhibitors it has been possible to study the organization of acetoacetate-activating systems i.e., the 3-ketoacid CoA-transferase reaction and the CoA ligase reaction. The former reaction is arsenate sensitive and ATP independent, the latter, which is ATP dependent, is compartmented in two different sites. The oxidation of acetoacetyl-CoA produced at one of these sites is carnitine dependent and appears to be disconnected from the oxidation site. Preliminary evidence has been obtained that the enzyme responsible for the reversible transfer of the acetoacetyl radical from carnitine to CoA is identifiable with the short-chain acetylcarnitine transferase. © 1969.