The dietary regulation of fatty acid synthesis de novo in two transplantable hepatomas, 7777 and 96188, has been studied by comparison of the acetyl coenzyme A carboxylase and fatty acid synthetase activities of tumor and host liver, both in animals fasted 48 hours and in those subsequently refed a fat-free diet for 48 hours. Neither acetyl-CoA carboxylase nor fatty acid synthetase of these hep...

Changes in the activities of acetyl-CoA carboxylase and HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) reductase were studied in primary cultures of adult-rat hepatocytes after exposure of the cells to insulin and/or carbohydrates. To determine the contribution of protein synthesis to changes in enzyme activity, the relative rate of synthesis of each enzyme was measured and the amount of translatable...

Fifty years ago, Kornberg and Krebs established the glyoxylate cycle as the pathway for the synthesis of cell constituents from C2-units. However, since then, many bacteria have been described that do not contain isocitrate lyase, the key enzyme of this pathway. Here, a pathway termed the ethylmalonyl-CoA pathway operating in such organisms is described. Isotopically labeled acetate and bicarbo...

In an earlier s tudy 1, 2 of leucine metabolism in crude heart extracts, da ta were obtained indicating that fl-methylcrotonyl CoA is acted upon by enoyl hydrase (crotonase) and tha t the resulting fl-hydroxyisovaleryl CoA is carboxylated enzymically in the presence of ATP to yield fl-hydroxy-fl-methylglutaryl CoA. This product is known 8 to be a t tacked by a specific cleavage enzyme to finnis...

The roles of synthesis and degradation in the regulation of acetyl coenzyme A carboxylase levels in rat liver following fasting and fat-free feeding have been studied. Antibodies prepared to homogeneous chicken liver acetyl-CoA carboxylase were shown to cross-react with rat liver acetyl-CoA carboxylase. Enzyme from both species was totally inactivated as well as precipitated by this antibody pr...

Acetyl-CoA carboxylase I (ACCase I) in developing oilseed rape embryos is predominantly cystosolic, based upon measurement of its propionyl-CoA carboxylase activity. Reduction of ACCase I by antisense expression reduces seed lipid content and affects carbohydrate metabolism.

The three protein components (biotin carboxylase, carboxyltransferase, and the biotin-containing carboxyl carrier protein of the acetyl coenzyme A carboxylase system have been resolved and purified extensively or to homogeneity from cell-free extracts of Escherichia co2i B. Carboxylation of acetyl-CoA to form malonyl-CoA requires the presence of all three components. Biotin carboxylase, which c...

heat-stable protein kinse inhibitor (50 units/ml), therefore ruling out the possibility that the protein kinase represents the free catalytic subunit of cyclic AMP-dependent protein kinase. Heparin, at a concentration of IOpg/ml, which inhibits the phosphorylation of acetyl-CoA carboxylase by casein kinase I and I1 (Tipper et al., 1983; Munday & Hardie, 1984) also had no effect on the phosphory...

The conditional mRNA transport mutant of Saccharomyces cerevisiae, acc1-7-1 (mtr7-1), displays a unique alteration of the nuclear envelope. Unlike nucleoporin mutants and other RNA transport mutants, the intermembrane space expands, protuberances extend from the inner membrane into the intermembrane space, and vesicles accumulate in the intermembrane space. MTR7 is the same gene as ACC1, encodi...