Peroxisome proliferator-induced acyl-CoA thioesterase from rat liver cytosol: molecular cloning and functional expression in Chinese hamster ovary cells.
We have isolated and cloned a cDNA that codes for one of the peroxisome proliferator-induced acyl-CoA thioesterases of rat liver. The deduced amino acid sequence corresponds to the major induced isoform in cytosol. Analysis and comparison of the deduced amino acid sequence with the established consensus sequences suggested that this enzyme represents a novel kind of esterase with an incomplete lipase serine active site motif. Analyses of mRNA and its expression indicated that the enzyme is significantly expressed in liver only after peroxisome proliferator treatment, but isoenzymes are constitutively expressed at high levels in testis and brain. The reported cDNA sequence is highly homologous to the recently cloned brain acyl-CoA thioesterase [Broustas, Larkins, Uhler and Hajra (1996) J. Biol. Chem. 271, 10470-10476], but subtle differences throughout the sequence, and distinct differences close to the resulting C-termini, suggest that they are different enzymes, regulated in different manners. A full-length cDNA clone was expressed in Chinese hamster ovary cells and the expressed enzyme was characterized. The palmitoyl-CoA hydrolysing activity (Vmax) was induced approx. 9-fold to 1 micromol/min per mg of cell protein, which was estimated to correspond to a specific activity of 250 micromol/min per mg of cDNA-expressed enzyme. Both the specific activity and the acyl-CoA chain length specificity were very similar to those of the purified rat liver enzyme.
Engberg
S T
ST
Stockholm University College of Health Sciences, Department of Biomedicine, Natural Science and Laboratory Science, Box 12773, S-112 96 Stockholm, Sweden.
Aoyama
T
T
Alexson
S E
SE
Hashimoto
T
T
Svensson
L T
LT
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D016466:CHO Cells; D002994:Clofibrate / Q000494:pharmacology; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000737:chemistry; D004051:Diethylhexyl Phthalate / Q000494:pharmacology; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008830:Microbodies / Q000187:drug effects; D008969:Molecular Sequence Data; D010170:Palmitoyl-CoA Hydrolase / Q000737:chemistry / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D018076:DNA, Complementary; D007527:Isoenzymes; D004051:Diethylhexyl Phthalate; D010170:Palmitoyl-CoA Hydrolase; D002994:Clofibrate