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Heat-treated high-fat diet modifies gut microbiota and metabolic markers in apoe-/- mice

BACKGROUND: High-fat diet has been known to have adverse effects on metabolic markers, as well as the gut microbiota. However, the effect of heat processing of high-fat diet, which leads to formations of advanced glycation end products (AGEs) has not been clearly distinguished from the effect of unheated fat. This study compared the effect of high-fat diet with heat-treated high-fat diet on adipos

Effects of signal peptide mutations on processing of Bacillus stearothermophilus α-amylase in Escherichia coli

Bacillus stearothermophilus α-amylase has a signal peptide typical for proteins exported by Gram-positive bacteria. There is only one signal peptidase processing site when the protein is exported from the original host, but when it is exported by Escherichia coli, two alternative sites are utilized. Site-directed mutagenesis was used to study the processing in E. coli. Processing sites for 13 B. s

Neuronal and non-neuronal catechol-O-methyltransferase in primary cultures of rat brain cells

Previous biochemical and histochemical studies have suggested that catechol-O-methyltransferase (COMT) is a predominantly glial enzyme in the brain. The aim of this work was to study its localization and molecular forms in primary cultures, where cell types can be easily distinguished with specific markers. COMT immunoreactivity was studied in primary astrocytic cultures from newborn rat cerebral

Kinetics of human soluble and membrane-bound catechol O- methyltransferase : A revised mechanism and description of the thermolabile variant of the enzyme

Human soluble (S) and membrane-bound (MB) catechol O-methyltransferase (COMT, EC 2.1.1.6) enzymes have been expressed at sufficiently high levels in Escherichia coil and in baculovirus-infected insect cells to allow kinetic characterization of the enzyme forms. The use of tight-binding inhibitors such as entacapone enabled the estimation of actual enzyme concentrations and, thereby, comparison of

O-methylation of L-dopa in melanin metabolism and the presence of catechol-O-methyltransferase in melanocytes.

O-Methylation of L-dopa was investigated as a possible regulatory mechanism in melanin metabolism. The methylation product of L-dopa, 3-O-methoxytyrosine was detected in extracts of cultured human melanocytes. The enzyme catechol-O-methyltransferase is responsible for this O-methylation and that of the dihydroxyindolic intermediates of melanogenesis. The enzyme is present in melanocytes in its sol

Distribution of catechol-O-methyltransferase enzyme in rat tissues

In the present study we show the distribution of catechol-O- methyltransferase (COMT) in various rat tissues with a highly specific antiserum prepared against recombinant rat COMT. Immunoprecipitation and immunocytochemical controls confirmed the COMT-specificity of the antibodies. The antiserum detected both the 24 KD soluble and the 28 KD membrane-bound forms of the enzyme. By immunohistochemica

Binding of a new Ca2+ sensitizer, levosimendan, to recombinant human cardiac troponin C : A molecular modelling, fluorescence probe, and proton nuclear magnetic resonance study

The binding of a new calcium sensitizer, levosimendan, to human cardiac troponin C (cTnC) is described. Fluorescence studies done on dansylated recombinant human cTnC and a site-directed mutant showed that levosimendan modulated the calcium-induced conformational change in cTnC, and revealed the role of Asp-88 in the binding of the drug to the NH2-terminal domain of cTnC. Furthermore, NMR studies

Expression of enzymatically active rat liver and human placental catechol-O-methyltransferase in Escherichia coli; purification and partial characterization of the enzyme

To produce sufficient amounts of recombinant catechol-O-methyltransferase (COMT) for structural and functional studies the coding regions of the rat liver and human placental COMT genes have been introduced into a bacterial expression vector pKEX14. Recombinant COMT was produced in Escherichia coli up to 10% of total bacterial protein after the induction of the T7 RNA polymerase gene with isopropy

Aspartic proteinase from barley grains is related to mammalian lysosomal cathepsin D

Resting barley (Hordeum vulgare L.) grains contain acid-proteinase activity. The corresponding enzyme was purified from grain extracts by affinity chromatography on a pepstatin-Sepharose column. The pH optimum of the affinity-purified enzyme was between 3.5 and 3.9 as measured by hemoglobin hydrolysis and the enzymatic activity was completely inhibited by pepstatin a specific inhibitor of aspartic

Crystallization and preliminary X-ray investigation of a recombinant form of rat catechol O-methyltransferase

Rat catechol O-methyltransferase cDNA was introduced into an E. coli expression vector pKEX14, which utilizes the inducible T7 promoter. Active and soluble recombinant catechol O-methyltransferase was produced in bacteria and purified to electrophoretic homogeneity by chromatographic procedures. The purified enzyme has been crystallized by the method of vapor diffusion using polyethylene glycol as

Purification and partial sequence analysis of the soluble catechol-o-methyltransferase from human placenta : Comparison to the rat liver enzyme

Catechol-o-methyltransferase from human placenta was purified 1400-fold by hydroxyapatite adsorption, ammonium sulfate precipitation, gel filtration, high performance anion- exchange and reversed-phase chromatography. The purified enzyme has an apparent molecular weight of 26.000, an isoelectric point of 5,3 and is activated ten-fold in the presence of 20mM cysteine. The enzyme shows primary struc

Molecular cloning and characterization of rat liver catechol-O-methyltransferase

The coding sequence of rat liver catechol-O-methyl-transferase (COMT; EC 2.1.1.6) was determined from rat cDNA and genomic libraries were screened with DNA probes and specific antiserum. The open reading frame consisted of 663 nucleotides coding for a 221-amino acid (aa) polypeptide with a deduced Mr of 24747. No obvious hydrophobic signal sequence, membrane-spanning domains, or potential N-glycos

Purification and partial characterization of rat liver soluble catechol- O-methyltransferase

The rat liver soluble catechol-O-methyltransferase (EC 2.1.1.6.) has been purified utilizing a combination of conventional chromatography and HPLC. The purified enzyme has a molecular mass of 25 kDa, a pI of 5.1, and exists in two forms which differ in the nature of their intramolecular disulfide bonds. This difference causes these two protein forms to behave differently in reversed phase chromato

Suppression of growth defects of α-amylase secreting Escherichia coli by signal sequence fusion

Two fusions of the Bacillus stearothermophilus α-amylase gene (amyS) with lacpoZ′ were constructed. The first, being a transcriptional fusion, placed amyS directly under lac promoter control eliminating interference by the endogenous promoter. IPTG induction of amyS transcription in this construction resulted in liberation of periplasmic proteins and eventually cell lysis. The other fusion replace

Dysfunction of Circulating Polymorphonuclear Leukocytes and Monocytes in Ambulatory Cirrhotics Predicts Patient Outcome

BACKGROUND: Cirrhosis represents a state of functional immune paresis with increased infection risk.AIMS: To investigate polymorphonuclear (PMN) leukocyte and monocyte function in ambulatory cirrhotics, and their potential relation with cirrhosis etiology or patient outcome.METHODS: Consecutive ambulatory cirrhotics without current or recent ( 0.05 for all). In Cox regression analysis, increased s