Search results for "glutamate dehydrogenase"

Direct Sensing of Nutrients via a LAT1-like Transporter in Drosophila Insulin-Producing Cells

2016

Summary Dietary leucine has been suspected to play an important role in insulin release, a hormone that controls satiety and metabolism. The mechanism by which insulin-producing cells (IPCs) sense leucine and regulate insulin secretion is still poorly understood. In Drosophila, insulin-like peptides (DILP2 and DILP5) are produced by brain IPCs and are released in the hemolymph after leucine ingestion. Using Ca2+-imaging and ex vivo cultured larval brains, we demonstrate that IPCs can directly sense extracellular leucine levels via minidiscs (MND), a leucine transporter. MND knockdown in IPCs abolished leucine-dependent changes, including loss of DILP2 and DILP5 in IPC bodies, consistent wit…

Vitamin B12 and hepatic enzyme serum levels correlate in male alcohol-dependent patients.

2001

- Vitamin B12 serum levels and markers for alcohol consumption were determined in 80 male alcohol-dependent patients. Spearman correlation coefficients (r(S)) were calculated. Significant positive correlations between vitamin B12 and hepatic enzyme values were found (gamma-glutamyltransferase: r(S) = 0.58; alanine aminotransferase: r(S) = 0.43; aspartate aminotransferase: r(S) = 0.47; glutamate dehydrogenase: r(S) = 0.43; all P:0.001). Therefore, for a proper interpretation of vitamin B12 levels, it may be clinically relevant to take markers of hepatocellular damage into account.

Ultra-long-distance running and the liver.

1990

During an ultra-long-distance race (1000 km in 20 days) the influence of running was examined on the enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), gamma-glutamyl-transferase (GGT), and glutamate dehydrogenase (GLDH) with regard to their release from the liver cells or their induction. Furthermore the liver synthetic capacity was assayed by measuring the enzyme activity of cholinesterase and the concentration of serum albumin during the race. Of the 110 participants, 55 finished the race and only the results of these runners were used in our study. AP increased continuously from day 0 (mean = 102 U/L) to day 19 (mean = 120 U/L). A fivefo…

Determination of molecular mass, Stokes' radius, frictional coefficient and isomer-type of non-denatured proteins by time-dependent pore gradient gel…

1988

Molecular mass, Stoke's radius, frictional coefficient and isomer-type of non-denatured proteins can be obtained by time-dependent gradient gel electrophoresis by evaluating the resulting data using a two-step mathematical procedure. Provided a histochemical staining procedure is available to locate the position of an enzyme in the gel, crude cell extracts can be used for estimating their molecular size properties. The computation of molecular properties of non-denatured proteins is demonstrated for isozymes of aspartate aminotransferase (EC 2.6.1.1), peroxidase (EC 1.11.1.42) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) from current-year needles of spruce. The resulting data as well…

Metabolism of the anaerobic formation of succinic acid bySaccharomyces cerevisiae

1978

1. Succinic acid is formed in amounts of 0.2–1.7 g/l by fermenting yeasts of the genusSaccharomyces during the exponential growth phase. No differences were observed between the various species, respiratory deficient mutants and wild type strains. 2. At low glucose concentrations the formation of succinic acid depended on the amount of sugar fermented. However, the nitrogen source was found to be of greater importance than the carbon source. 3. Of all nitrogen sources, glutamate yielded the highest amounts of succinic acid. Glutamate led to an oxidative and aspartate to a reductive formation of succinic acid. 4. A reductive formation of succinic acid by the citric acid cycle enzymes was obs…

Improved nitrogen metabolism in rats fed on lipid-rich liquid diets

1994

N metabolism was studied in young rats fed on lipid-rich, isonitrogenous, purified liquid diets, a convenient and easy technique for inducing voluntary overfeeding of energy and lipids under controlled nutritional conditions. Overfed rats showed a marked N retention at the expense of a reduced production of urea. The capacities of isolated hepatocytes to synthesize urea and glucose from added precursors were greatly diminished. The activities of the urea cycle enzymes and several enzymes involved in the availability of NH3, for this pathway were concomitantly reduced in overfed animals. Therefore, our results showed an improved N metabolism in overfed rats promoted by the overfeeding of lip…

2019

The Gram-positive soil bacterium Bacillus subtilis relies on the glutamine synthetase and the glutamate synthase for glutamate biosynthesis from ammonium and 2-oxoglutarate. During growth with the carbon source glucose, the LysR-type transcriptional regulator GltC activates the expression of the gltAB glutamate synthase genes. With excess of intracellular glutamate, the gltAB genes are not transcribed because the glutamate-degrading glutamate dehydrogenases (GDHs) inhibit GltC. Previous in vitro studies revealed that 2-oxoglutarate and glutamate stimulate the activator and repressor function, respectively, of GltC. Here, we have isolated GltC variants with enhanced activator or repressor fu…

NovelAmycolatopsis balhimycinabiochemical abilities unveiled by proteomics

2014

Amycolatopsis balhimycina DSM5908 is an actinomycete producer of balhimycin, an analogue of vancomycin, the antibiotic of ‘last resort’ against multidrug-resistant Gram-positive pathogens. Most knowledge on glycopeptide biosynthetic pathways comes from studies on A. balhimycina as this strain, among glycopeptide producers, is genetically more amenable. The recent availability of its genome sequence allowed to perform differential proteomic analyses elucidating key metabolic pathways leading to antibiotic production in different growth conditions. To implement proteomic data on A. balhimycina derived from 2-DE approaches and to identify novel components, a combined approach based on protein …

Messung der gesamtaktivität von glutamat-oxalacetat-transaminase in leberhomogenaten

1971

Abstract A method is described, suitable for routine measurements of the total glutamicoxaloacetic transaminase activity in a large number of liver samples by treatment of homogenates with the detergent Triton X-100. Comparison with other methods and with results of other investigators shows that this method is superior. Neither sonic treatment nor freezing and thawing leads to a complete liberation of the mitochondrial transaminase activity. A number of other enzyme activities can be assayed in Triton-treated homogenates, such as glutamic-pyruvic transaminase, glutamate dehydrogenase, NADP-isocitric dehydrogenase, lactate dehydrogenase, and malate dehy drogenase, β-Hydroxybutyrate dehydrog…

Preparation of extracts from mature spruce needles for enzymatic analyses

1987

It was possible to extract simultaneously several active enzymes involved in the carbohydrate or the amino acid metabolism from spruce needles [Picea abies (L.) Karst.] when a) a 100 mM Na-Pi buffer of pH 7.5 containing 5% PVPP and 0.5% Triton X-100 was used and when b) the resulting crude extracts were freed from lowmolecular-weight compounds by gel-chromatography using the separation medium Fractogel TSK HW-40. Besides Triton X-100, Triton X-305, Myrij-52 and Brij-35 were tested, but 0.5% Triton X-100 brought about the most active enzyme extracts. In crude extracts prepared from spruce needles during the early summer a high increase in absorbance at 334 nm was observed when the co-substra…