Insulin stimulates fatty acid synthesis in white and brown fat cells as well as in liver and mammary tissue. Hormones that increase cellular cyclic AMP concentrations inhibit fatty acid synthesis, at least in white adipose tissue and liver. These changes in fatty acid synthesis occur within minutes. In white fat cells, they are brought about not only by changes in glucose transport but also cha...

Modulatory effects of l-carnitine, acetate, propionate, and 5-tetradecyloxy-2-furoic acid (TOFA; an inhibitor acetyl-CoA carboxylase) on oxidation esterification [1-14C]-palmitate were studied in hepatocytes isolated from phlorizin-treated control wethers. Our hypotheses that (1) palmitate would be greater sheep injected with phlorizin; (2) l-carnitine increase more (3) acetate propionate decre...

Fluazifop is a grass-selective herbicide that appears to act by inhibiting fatty acid synthesis de novo in sensitive species. Results from four different types of experiment show that this inhibition is due to an action of fluazifop on acetyl-CoA carboxylase and not on fatty acid synthetase. The acetyl-CoA carboxylase from sensitive barley (Hordeum vulgare), but not from resistant pea (Pisum sa...

Recent investigations in this laboratory have shownl 2 that the isocitrate(or citrate-) activated form of liver acetyl CoA carboxylase (E.C. 6.4.1.2) is a large protein structure having a molecular weight of about four million. Electron microscopic examination of the carboxylase in the presence of isocitrate reveals' that it has a filamentous structure with dimensions of SG-100 A by up to 5000 ...

Rat liver acetyl-CoA carboxylase has been purified to homogeneity by a new method involving polyethylene glycol precipitation, and DEAE and Sepharose 4B chromatography. The final product displays a single band on SDS polyacrylamide gel electrophoresis of estimated molecular weight 240,000. This material contains 5.5 +/- 0.3 moles of alkali-labile phosphate per subunit and has a specific activit...

A high molecular weight protein (approximately 1.5--2 x 10(6) daltons) has been found in rat liver cytosol to inhibit acetyl CoA carboxylase activity. The protein inhibitor was purified by ammonium sulfate precipitation, DEAE-cellulose chromatography and gel filtration. The inactivation of the carboxylase is not attributable to either phosphorylation of the enzyme or to action on substrates or ...

Acetyl-CoA carboxylase, the major flux determining enzyme for lipogenesis is controlled both acutely through reversible phosphorylation [ I ] and chronically through changes in gene transcription [2] Regulation of the acetyl-CoA carboxylase gene is complex due to the use of a dual promoter system and alternative exon splicing resulting in transcripts with the same open reading frame but with he...

The activity of the biotin-dependent enzyme pyruvate carboxylase from many organisms is highly regulated by the allosteric activator acetyl-CoA. A number of X-ray crystallographic structures of the native pyruvate carboxylase tetramer are now available for the enzyme from Rhizobium etli and Staphylococcus aureus. Although all of these structures show that intersubunit catalysis occurs, in the c...

The activities of two lipogenic enzymes, acetyl-CoA carboxylase and fatty acid synthase, were determined in two transplantable mammary adenocarcinomas (13762 and R3230AC) carried by non-pregnant, pregnant and lactating rats, and in mammary tissue of control animals (non-tumour-carrying) of comparable physiological states. During mammary-gland differentiation of control or tumour-carrying animal...