L. Hildebrandt et al., ACYL COA AND LIPID-SYNTHESIS FROM KETONE-BODIES BY THE EXTRAMITOCHONDRIAL FRACTION OF HEPATOMA TISSUE, Biochemical and biophysical research communications, 225(1), 1996, pp. 307-312
The compartmentation of the pathway for the synthesis of lipids from k
etone bodies was examined in a cell free, post-mitochondrial supernata
nt fraction of malignant Morris hepatoma 7777 tissue. A fortified supe
rnatant system effectively incorporated radioactive D(-)-3-hydroxybuty
rate and acetoacetate into cholesterol and fatty acids, and both keton
e bodies were directly converted to their CoA thioesters. Furthermore,
a microsome-free (100,000 Xg) cytosolic fraction was also able to acy
late 3-hydroxybutyrate to 3-hydroxybutyryl CoA. No previous identifica
tion of this enzyme activity has been described. These results which c
haracterize a distinct extramitochondrial pathway for conversion of 3-
hydroxybutyrate as well as acetoacetate into lipids also suggest the p
ossibility of a previously undetected enzymatic activity for utilizati
on of this ketone body. (C) 1996 Academic Press, Inc.