Kinetic characterization of long chain fatty acyl coenzyme A ligase from rat liver mitochondria.
Long chain fatty acyl coenzyme A ligase (EC 6.2.1.3) purified from rat liver mitochondria has been characterized with respect to several kinetic parameters. Many of the kinetic properties of the mitochondrial enzyme are similar to those of the purified microsomal enzyme with respect to palmitoyl-CoA formation, but there are distinct differences. The fatty acid and nucleotide specificities of the mitochondrial enzyme are similar to those of the microsomal enzyme, as are the apparent Km values for ATP and coenzyme A. On the other hand, the mitochondrial enzyme differs from the microsomal enzyme in that it has a lower pH optimum, is different in molecular weight, and does not show simple saturation kinetics with palmitate as substrate. Of particular interest is the evidence presented which indicates that the mitochondrial long chain fatty acyl-CoA ligase, unlike short and medium chain ligases, does not utilize an acyladenylate as an intermediate in the formation of fatty acyl-CoA.
D000818:Animals; D003066:Coenzyme A Ligases / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology*; D010171:Palmitoyl Coenzyme A; D051381:Rats; D013379:Substrate Specificity
D010171:Palmitoyl Coenzyme A; D003066:Coenzyme A Ligases