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...

BACKGROUND In microorganisms lacking a functional glyoxylate cycle, acetate can be assimilated by alternative pathways of carbon metabolism such as the ethylmalonyl-CoA (EMC) pathway. Among the enzymes converting CoA-esters of the EMC pathway, there is a unique carboxylase that reductively carboxylates crotonyl-CoA, crotonyl-CoA carboxylase/reductase (Ccr). In addition to the EMC pathway, gene ...

We have identified single genes encoding homologues of the alpha, beta and gamma subunits of mammalian AMP-activated protein kinase (AMPK) in the genome of Drosophila melanogaster. Kinase activity could be detected in extracts of a Drosophila cell line using the SAMS peptide, which is a relatively specific substrate for the AMPK/SNF1 kinases in mammals and yeast. Expression of double stranded (...

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...

Acetyl-CoA carboxylase is found in all animals, plants, and bacteria and catalyzes the first committed step in fatty acid synthesis. It is a multicomponent enzyme containing a biotin carboxylase activity, a biotin carboxyl carrier protein, and a carboxyltransferase functionality. Here we report the X-ray structure of the biotin carboxylase component from Escherichia coli determined to 2.4-A res...

Plastidic acetyl-coenzyme A (CoA) carboxylase (ACCase) catalyzes the first committed reaction of de novo fatty acid biosynthesis. This heteromeric enzyme is composed of one plastid-coded subunit (beta-carboxyltransferase) and three nuclear-coded subunits (biotin carboxy-carrier, biotin carboxylase, and alpha-carboxyltransferase). We report the primary structure of the Arabidopsis alpha-carboxyl...