Arundinella hirta L. is a C(4) plant having an unusual C(4) leaf anatomy. Besides mesophyll and bundle sheath cells, A. hirta leaves have specialized parenchyma cells which look morphologically like bundle sheath cells but which lack vascular connections and are located between veins, running parallel to them. Activities of phosphoenolpyruvate and ribulose-1,5-bisphosphate carboxylases and phos...

Catecholamines induced an increase in the activity of rat adipose tissue and liver phosphopyruvate carboxylases that was maintained for 48h. The response of adipose tissue phosphopyruvate carboxylase was blocked by actinomycin D, corticosteroids and propranolol, whereas corticosteroids and propranolol did not affect the liver enzyme. Cortisol phosphate, like actinomycin D, interfered only with ...

Holocarboxylase synthetase (HCS) catalyzes the biotinylation of five carboxylases in human cells, and mutations of HCS cause multiple carboxylase deficiency (MCD). Although HCS also participates in the regulation of its own mRNA levels, the relevance of this mechanism to normal metabolism or to the MCD phenotype is not known. In this study, we show that mRNA levels of enzymes involved in biotin...

Holocarboxylase synthetase (HLCS) catalyzes the covalent attachment of biotin to cytoplasmic and mitochondrial carboxylases, nuclear histones, and over a hundred human proteins. Nonhydrolyzable ketophosphonate (β-ketoP) and hydroxyphosphonate (β-hydroxyP) analogs of biotin-5'-AMP inhibit holocarboxylase synthetase (HLCS) with IC50 values of 39.7 μM and 203.7 μM. By comparison, an IC50 value of ...

Fatty acids are a major energy source and important constituents of membrane lipids, and they serve as cellular signaling molecules that play an important role in the etiology of the metabolic syndrome. Acetyl-CoA carboxylases 1 and 2 (ACC1 and ACC2) catalyze the synthesis of malonyl-CoA, the substrate for fatty acid synthesis and the regulator of fatty acid oxidation. They are highly regulated...

Acetyl-coenzyme A carboxylases (ACCs) have crucial roles in fatty acid metabolism. The biotin carboxylase (BC) subunit of Escherichia coli ACC is believed to be active only as a dimer, although the crystal structure shows that the active site of each monomer is 25 A from the dimer interface. We report here biochemical, biophysical, and structural characterizations of BC carrying single-site mut...

The essential vitamin biotin is a covalent and tenaciously attached prosthetic group in several carboxylases that play important roles in the regulation of energy metabolism. Here we describe increased acetyl-CoA levels and mitochondrial hyperacetylation as downstream metabolic effects of biotin deficiency. Upregulated mitochondrial acetylation sites correlate with the cellular deficiency of th...