The vitamin K-dependent gamma-glutamyl carboxylase catalyzes the posttranslational conversion of glutamic acid to gamma-carboxyglutamic acid, an amino acid critical to the function of the vitamin K-dependent blood coagulation proteins. Given the functional similarity of mammalian vitamin K-dependent carboxylases and the vitamin K-dependent carboxylase from Conus textile, a marine invertebrate, ...

The enzymic properties of ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase purified from rice (Oryza sativa L.) leaves were studied. Rice RuBPcarboxylase, activated by preincubation with CO(2) and Mg(2+) like other higher plant carboxylases, had an activation equilibrium constant (K(c)K(Mg)) of 1.90 x 10(5) to 2.41 x 10(5) micromolar(2) (pH 8.2 and 25 degrees C). Kinetic parameters of car...

A novel acetone-degrading, nitrate-reducing bacterium, strain KN Bun08, was isolated from an enrichment culture with butanone and nitrate as the sole sources of carbon and energy. The cells were motile short rods, 0.5 to 1 by 1 to 2 μm in size, which gave Gram-positive staining results in the exponential growth phase and Gram-negative staining results in the stationary-growth phase. Based on 16...

Late-onset multiple carboxylase deficiency is characterized clinically by skin rash, alopecia, seizures and ataxia and occasionally by candidiasis and developmental delay. Biochemically, these individuals exhibit findings consistent with a combined deficiency of the biotin-dependent carboxylases. We have found that the activity of the enzyme biotinidase is also deficient in the sera of five aff...

BACKGROUND Several studies have shown that biotin affects glucose homeostasis. Serum biotin concentrations are lower in subjects with type 2 diabetes than in control subjects. Lymphocyte propionyl-CoA carboxylase (PCC; EC 6.4.1.3) activity has proved to be a sensitive indicator of biotin status that is more accurate than is serum biotin concentration. OBJECTIVE We studied the activity of PCC,...

Biotin is a water-soluble vitamin required by all organisms, but only synthesized by plants and some bacterial and fungal species. As a cofactor, biotin is responsible for carbon dioxide transfer in all biotin-dependent carboxylases, including acetyl-CoA carboxylase, methylcrotonyl-CoA carboxylase, and pyruvate carboxylase. Adding biotin to carboxylases is catalyzed by the enzyme holocarboxylas...

Biotin is a necessary cofactor of numerous biotin-dependent carboxylases in a variety of microorganisms. The strict control of biotin biosynthesis in Escherichia coli is mediated by the bifunctional BirA protein, which acts both as a biotin-protein ligase and as a transcriptional repressor of the biotin operon. Little is known about regulation of biotin biosynthesis in other bacteria. Using com...

Studies of the response of phosphoenolpyruvate carboxylase from C(3) (wheat [Triticum aestivum L.]), C(4) (maize [Zea mays L.]), and Crassulacean acid metabolism (CAM) (Crassula) leaves to the activator glucose-6-phosphate as a function of pH showed that the binding of the activator and the response path to activation were essentially identical for all three enzymes. The level of affinity for t...