The phosphoenolpyruvate carboxylase (PEPC) interactome of developing castor oil seed (COS; Ricinus communis) endosperm was assessed using coimmunopurification (co-IP) followed by proteomic analysis. Earlier studies suggested that immunologically unrelated 107-kD plant-type PEPCs (p107/PTPC) and 118-kD bacterial-type PEPCs (p118/BTPC) are subunits of an unusual 910-kD hetero-octameric class 2 PE...

Degradation of the aromatic ketone acetophenone is initiated by its carboxylation to benzoylacetate catalyzed by acetophenone carboxylase (Apc) in a reaction dependent on the hydrolysis of two ATP to ADP and Pi. Apc is a large protein complex which dissociates during purification into a heterooctameric Apc(αα'βγ)2 core complex of 482 kDa and Apcε of 34 kDa. In this report, we present the X-ray ...

Acetyl-CoA carboxylases (ACC1 and ACC2) catalyze the carboxylation of acetyl-CoA to form malonyl-CoA, an intermediate metabolite that plays a pivotal role in the regulation of fatty acid metabolism. We previously reported that ACC2 null mice are viable, and that ACC2 plays an important role in the regulation of fatty acid oxidation through the inhibition of carnitine palmitoyltransferase I, a m...

Carbon isotope fractionation by structurally and catalytically distinct ribulose-1,5-bisphosphate carboxylases from one eucaryotic and four procaryotic organisms has been measured under nitrogen. The average fractionation for 40 experiments was -34.1 per thousand with respect to the delta(13)C of the dissolved CO(2) used, although average fractionations for each enzyme varied slightly: spinach ...

The gasification of organic waste materials to synthesis gas (syngas), followed by microbial fermentation, provides a significant resource for generating bioproducts such as polyhydroxyalkanoates (PHA). The anaerobic photosynthetic bacterium, Rhodospirillum rubrum, is an organism particularly attractive for the bioconversion of syngas into PHAs. In this study, a quantitative physiological analy...

We have cloned and characterized the gene PYC1, encoding the unique pyruvate carboxylase in the dimorphic yeast Yarrowia lipolytica. The protein putatively encoded by the cDNA has a length of 1,192 amino acids and shows around 70% identity with pyruvate carboxylases from other organisms. The corresponding genomic DNA possesses an intron of 269 bp located 133 bp downstream of the starting ATG. I...

Holocarboxylase synthetase (HCS), catalyzing the covalent attachment of biotin, is ubiquitously represented in living organisms. Indeed, the biotinylation is a post-translational modification that allows the transformation of inactive biotin-dependent carboxylases, which are committed in fundamental metabolisms such as fatty acid synthesis, into their active holo form. Among other living organi...

Protein biotinylation is an original and very specific posttranslational modification, compartmented in plants, between mitochondria, plastids, and the cytosol. This reaction modifies and activates few carboxylases committed in key metabolisms and is catalyzed by holocarboxylase synthetase (HCS). The molecular bases of this complex compartmentalization and the relative function of each of the H...

Acetyl-CoA carboxylases (ACCs) are crucial metabolic enzymes and have been targeted for drug development against obesity, diabetes, and other diseases. The carboxyltransferase (CT) domain of this enzyme is the site of action for three different classes of herbicides, as represented by haloxyfop, tepraloxydim, and pinoxaden. Our earlier studies have demonstrated that haloxyfop and tepraloxydim b...