Incubation of isolated hepatocytes with glutamine or proline or in hypotonic media is known to activate glycogen synthase and acetyl-CoA carboxylase as a result of cell swelling. We report here that the same experimental conditions caused an activation of phosphatidylinositol 3-kinase and p70 ribosomal protein S6 kinase (p70 S6 kinase) but did not modify the activity of p42 mitogen-activated pr...

Oxalacetate synthesis catalyzed by pyruvate carboxylase from rat liver in the absence of acetyl-CoA exhibits a pH dependence and specificity for activation by univalent and divalent cations similar to that reported previously for acetylCoA-dependent oxalacetate synthesis by this enzyme (McCLURE, W. R., LARDY, H. A., AND KNEIFEL, H. P. (1971) J. Biol. Chem. 246, 3569-3578). Fractionation studies...

Oxalacetate synthesis catalyzed by pyruvate carboxylase from rat liver in the absence of acetyl-CoA exhibits a pH dependence and specificity for activation by univalent and divalent cations similar to that reported previously for acetylCoA-dependent oxalacetate synthesis by this enzyme (McCLURE, W. R., LARDY, H. A., AND KNEIFEL, H. P. (1971) J. Biol. Chem. 246, 3569-3578). Fractionation studies...

Neutral lipids, especially triacylglycerols, accumulated due to myo-inositol deficiency both in the cells of Saccharomyces carlsbergensis (Hayashi et al. (1976) J. Biol. Chem., 251, 5759--5769) and in the liver of the rat (Hayashi et al. (1974) Biochim. Biophys. Acta, 360, 134--155). The accumulation of triacylglycerols in the deficient yeast resulted, at least partly, from an enhancement of ac...

1. The effect of nutritional status on fatty acid synthesis in brown adipose tissue was compared with the effect of cold-exposure. Fatty acid synthesis was measured in vivo by 3H2O incorporation into tissue lipids. The activities of acetyl-CoA carboxylase and fatty acid synthetase and the tissue concentrations of malonyl-CoA and citrate were assayed. 2. In brown adipose tissue of control mice, ...

Pahnitoyl-CoA (100 PM), in the presence of albumin (24 mg per ml), inhibited the incorporation of [14C]citrate into fatty acids in a cytosol fraction of chick liver and inhibited the activity of acetyl-CoA carboxylase purified from chick liver. Under similar incubation conditions, pahnitoyl-CoA (ZOO PM) did not inhibit fatty acid synthetase, ATP-citrate lyase, malic enzyme, NADP-linked isocitra...

The ubiquitous acetyl-CoA carboxylase is a pivotal enzyme in the synthesis of fatty acids in both eukaryotes and prokaryotes. The importance of this enzyme is needed in the initiating reaction for synthesizing fatty acids, which are very important when used as fuel molecules and providing the building blocks of biological membranes. Acetyl-CoA carboxylase catalyzes the committed step in making ...

A normal mash diet or a single glucose injection stimulates fatty acid synthesis and increases the total activities of acetyl coenzyme A carboxylase, fatty acid synthetase, and malic enzyme in the livers of neonatal chicks. Feeding and glucose injection caused a decrease in the concentration of free fatty acids and fatty acyl-CoA and an increase in CYglycerophosphate and free CoA. These concent...

Biotin-containing proteins are found in all forms of life, and they catalyze carboxylation, decarboxylation, or transcarboxylation reactions that are central to metabolism. In plants, five biotin-containing proteins have been characterized. Of these, four are catalysts, namely the two structurally distinct acetyl-CoA carboxylases (heteromeric and homomeric), 3-methylcrotonyl-CoA carboxylase and...

ses the first step in this pathway and its activity is regulated allosterically, e.g. citrate (activator) and long-chain fatty acyl-CoA (inhibitor), and by reversible phosphorylation (Hardie, 1980; Hardie et al., 1984). It is thus a prime candidate for such specific inhibition. In the lactating mammary gland, 24 h starvation inhibits lipogenesis by 98% and this is accompanied by an inhibition o...