Acetyl-CoA carboxylase, the rate-limiting enzyme in the biogenesis of long-chain fatty acids, is regulated by phosphorylation and dephosphorylation. The major phosphorylation sites that affect carboxylase activity and the specific protein kinases responsible for phosphorylation of different sites have been identified. A form of acetyl-CoA carboxylase that is independent of citrate for activity ...

Acetyl-CoA Carboxylase, Acetyl-CoA Synthetase, Light Dependence o f Fatty Acid Synthesis in Chloroplasts In analogy to chloroplast fatty acid synthesis from acetate the key enzymes o f acetate fixation, acetyl-CoA synthetase and acetyl-CoA carboxylase, in rapidly Triton X-100 lysed spinach chloroplasts show an activation by light and deactivation in the dark. The stimulation o f acetyl-CoA carb...

Acetyl-CoA carboxylase phosphatase has been purified from the rat epididymal fat pad. The phosphatase occurs in a complex with the carboxylase. In the purification of the phosphatase, the high molecular weight complex was initially separated by sucrose gradient centrifugation, and the phosphatase was isolated from the complex by adjusting to 80% saturation with ethanol and by chromatography on ...

Acetyl-CoA carboxylase is regulated allosterically by citrate and covalently by a phosphorylation/dephosphorylation mechanism. We have isolated and purified from rat livers a novel kinase that phosphorylates and inactivates the carboxylase. This kinase is bound to the carboxylase and can be eluted in salt-rich solution. The native kinase exists as high molecular weight aggregates of a subunit t...

1. Pyruvate carboxylase from baker's yeast is inhibited by ADP, AMP and adenosine at pH8.0 in the presence of magnesium chloride concentrations equal to or higher than the ATP concentration. The adenine moiety is essential for the inhibitory effect. 2. In the absence of acetyl-CoA (an allosteric activator) ADP, AMP and adenosine are competitive inhibitors with respect to ATP. In the presence of...

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...

The 3-hydroxypropionate cycle is a new autotrophic CO(2) fixation pathway in Chloroflexus aurantiacus and some archaebacteria. The initial step is acetyl-coenzyme A (CoA) carboxylation to malonyl-CoA by acetyl-CoA carboxylase, followed by NADPH-dependent reduction of malonyl-CoA to 3-hydroxypropionate. This reduction step was studied in Chloroflexus aurantiacus. A new enzyme was purified, malon...

Enzymically inactive acetyl-CoA carboxylase [acetyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] was found as a component of bovine milk-fat-globule membrane (MFGM). Acetyl-CoA carboxylase was present in MFGM at a higher concentration than in cytosolic or mitochondrial fractions of bovine mammary tissue, which makes it unlikely that its presence was due to simple contamination by these ...

Acetyl-CoA carboxylase was isolated from rat liver by polyethylene glycol precipitation and avidin affinity chromatography. Sodium dodecyl sulfate electrophoresis of the enzyme gives one protein band (Mr 250,000). Phosphate analysis of the carboxylase showed the presence of 8.3 mol of phosphate/mol of subunit (Mr 250,000). The purified carboxylase has low activity in the absence of citrate (spe...

Acetyl-CoA carboxylase catalyzes the carboxylation of acetyl-CoA to malonyl-CoA. This reaction constitutes the first committed step of fatty acid synthesis in most organisms, while its product also serves as a universal precursor for various other high-value compounds. The important regulatory and rate-limiting role of acetyl-CoA carboxylase makes this enzyme a powerful tool in a variety of bio...