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PubMed1979

Fumarate reductase of Escherichia coli. Elucidation of the covalent-flavin component.

Fumarate reductase is a membrane-bound terminal oxidase which is induced when Escherichia coli is grown anaerobically. The purified enzyme is composed of two polypeptide chains of 69,000 and 24,000 daltons and contains 1 mol of covalently bound flavin adenine dinucleotide per mol of enzyme. Fluorescence scanning of SDS-polyacrylamide gels of the protein shows that the flavin is attached to the large subunit. The hypsochromic shift of the 372 nm band of riboflavin to 350 nm in both native fumarate reductase and a flavin peptide released by proteolytic digestion indicates that the flavin is attached via position 8 alpha of riboflavin. Based on the spectral properties and pH-fluorescence dependence we have identified the linkage as 8 alpha-[N(3)-histidyl]FAD.

Escherichia coli↗
PubMed1984

[Dissociation constants of succinate dehydrogenase complexes with succinate, fumarate and malonate].

The rates of the oxidized (Eox) and reduced (Ered) (by NAD . H through the ubiquinone pool) succinate dehydrogenase inhibition by N-ethyl-maleimide are equal and obey pseudo-first order kinetics. The protection of the enzyme against irreversible alkylation was used to quantitate the dissociation constants for Eox and Ered complexes with fumarate, succinate and malonate under conditions when no intramolecular redox reactions might occur. the membrane-bound succinate dehydrogenase catalyzes the succinate : phenazine-methosulphate reductase reaction in the presence of thenoyltrifluoroacetone by a Slater-Bonner mechanism. A comparison of the constants measured by the protection with those derived from the steady-state kinetics shows that succinate affinity for Eox is about 10 times higher than that for Ered; the reverse relations were found for fumarate, whereas the affinity for malonate only slightly depends on the redox state of the enzyme. The data obtained suggest that the dicarboxylate binding at the active site induces changes in the enzyme redox potential. The surface charge does not contribute significantly to the energy of the dicarboxylate binding to the active site of the membrane-bound enzyme.

Animals↗
PubMed1981

Antitumor and anti-intoxication activities of fumaric acid in cultured cells.

Fumaric acid, isolated as the active component of Capsella bursa-pastoris herb for inhibiting the solid growth of Ehrlich tumor in mice, was found to reduce markedly the growth and viability of Ehrlich, MH134, and L1210 mouse tumor cells in culture at concentration of 0.3 approximately 1.2 mg/ml. In contrast, fumaric acid at these concentrations in the culture medium had no deleterious effect on the monolayer development of mouse and chick embryo cells but exhibited activity to enhance the recovery of the cells from the toxic effects of mitomycin C, aflatoxin B1, N-methyl-N'-nitro-N-nitrosoguanidine, and potassium 1-methyl-7-[2-(5-nitro-2-furyl) vinyl]-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate.

Animals↗
PubMed1976

Radiorespirometric studies in genus Neisseria. 2. The catabolism of glutamate and fumarate.

The catabolism of glutamate and fumarate was studied by radiorespirometry in selected Neisseria species. The tricarboxylic acid cycle is functioning in all species tested, in spite of the known absence of in vitro malate dehydrogenase activity in N. meningitidis, N. gonorrhoeae and N. cinerea. The results imply a pyridine nucleotide independent oxidation of malate. The oxidation of glutamate is less complete in the presence of phosphate. In N. meningitidis, N. perflava, N. flava, N. subflava and N. lactamica the catabolism of fumarate was slow and incomplete in the absence of glutamate.

Carbon Dioxide↗
PubMed1977

Inhibitory effect of fumaric acid and dicarboxylic acids on gastric ulceration in rats.

Production of gastric ulcerations in rats by pyloric ligation was found to be inhibited by either intraperitoneal or oral administration of fumaric acid in a dose of 50 mg per kg. The antiulcer action was also exhibited by the four-carbon dicarboxylic acids, maleic acid, oxalacetic acid, succinic acid and malic acid. The studies on fumaric acid indicated that the acid's antiulcer action was based on its ability to inhibit the gastric juice secretion and to dilate the stomach muscle.

Animals↗
PubMed1997

Bioavailability and pharmacokinetics of magnesium after magnesium fumarate administration in humans.

Bioavibility and pharmacokinetics of magnesium after magnesium fumarate administration in humans. The volunteers were given a single oral dose of 530 mg of magnesium on an empty stomach. The preparation was a magnesium fumarate tablet. The simplest formule to describe the course of blood magnesium concentration changes was a two exponential equation for an open monocompartmental model.

Adult↗
PubMed1992

Studies on the intravenous pharmacokinetics in rabbit and in vitro protein binding of two new salts of erythromycin: erythromycin maltobionate and erythromycin fumarate.

Pharmacokinetics in rabbits following intravenous administration and in vitro protein binding were studied for two new salts of erythromycin (erythromycin maltobionate and erythromycin fumarate). Serum erythromycin levels following intravenous injection were described by two compartment model kinetics, and values for the distribution volume of the central compartment, the peripheral compartment and overall distribution volume were calculated. The elimination half-lives of erythromycins in serum were 83 min, 168 min, and 103 min for erythromycin maltobionate, erythromycin fumarate, and erythromycin lactobionate (reference standard), respectively. The erythromycin salts were highly (c. 90 per cent) protein bound, but the binding was found to be reversible. Differences in the pharmacokinetic parameters after administration of equivalent doses of the salts, indicate possible variation in efficacies of different salts.

Animals↗
PubMedDate not supplied

Analgesic comparison of propiram fumarate with pentazocine, codeine, and placebo in postsurgical pain.

The safety and effectiveness of a single oral dose of 50 mg propiram fumarate as an analgesic was compared in a double-blind clinical trial trial against single doses of standard reference analgesics (50 mg pentazocine hydrochloride or 60 mg codeine sulfate) or placebo. Subjects were adult patients experiencing severe postsurgical pain. Mean pain scores and SPID scores showed all three active drugs to be favored (P less than 0.05) over placebo in patients with severe initial pain. The most common side effects seen were drowsiness, nausea, and dizziness. These were not severe enough to require treatment. Propiram fumarate (50 mg) was shown to be an effective and safe analgesic in the treatment of severe postsurgical pain.

Adolescent↗
PubMedDate not supplied

Analgesic effects of oral propiram fumarate, codeine sulfate and placebo in postoperative pain.

Our purpose was to evaluate the analgesic efficacy and safety of single oral doses of propiram fumarate 50 mg, codeine sulfate 60 mg and placebo in the relief of moderate to severe postoperative pain. One hundred and twenty patients completed a randomized, double-blind, single-dose, stratified, parallel-groups trial and were observed for either 4 or 6 hours. Based upon each of the summary efficacy measures--SPID, % SPID and TOTAL--propiram and codeine were approximately equally effective and both were statistically superior to placebo. Propiram was significantly more effective than codeine at hour 5 for Pain Intensity Difference. Two adverse effects were attributed to propiram. Propiram fumarate 50 mg is an effective oral analgesic similar to codeine sulfate 60 mg, with the possibility of a longer duration of action.

Adolescent↗
PubMed2002

Cell adhesion on poly(propylene fumarate-co-ethylene glycol) hydrogels.

We synthesized poly(propylene fumarate-co-ethylene glycol) block copolymers [P(PF-co-EG)] that were crosslinked to form hydrogels and investigated the effect of copolymer composition on cell adhesion to the hydrogels. These copolymers were water soluble when the molar ratio of ethylene glycol repeating unit to propylene fumarate repeating unit was higher than 4.4. The water content of swollen hydrogels increased from 29 to 63% and the water contact angle decreased from 38 to 21 degrees as the molar ratio increased from 0.6 to 4.4. No significant change in either property was observed for ratios higher than 4.4. In a cell adhesion assay under serum-free conditions, the number of adherent platelets and smooth muscle cells decreased from 21 to 2% and from 78 to 20% of the initial seeding density, respectively, as the molar ratio increased from 0.6 to 7.8. Adherent smooth muscle cells did not spread on the hydrogels of the compositions tested. Adherent platelets did not show any filopodia. These results suggest that the hydrophilicity of P(PF-co-EG) hydrogels is one of the factors affecting cell adhesion, and that copolymer modification may be required for enhancing cell adhesion for an application involving the copolymers as in situ crosslinkable cell carriers.

Biocompatible Materials↗
PubMed2003

Three-dimensional culture of differentiating marrow stromal osteoblasts in biomimetic poly(propylene fumarate-co-ethylene glycol)-based macroporous hydrogels.

This study assesses the ability of biomimetic poly(propylene fumarate-co-ethylene glycol)-based hydrogels to sustain the differentiation of marrow stromal cells (MSCs) to the osteoblastic phenotype and to produce a mineralized matrix in vitro. Macroporous hydrogels based on poly(propylene fumarate-co-ethylene glycol) with and without covalently linked RGD cell-adhesive peptide were synthesized and seeded with rat MSCs suspended in media or in a type I collagen solution. Cells suspended in media were found to adhere to RGD-modified but not to unmodified hydrogels. Cells suspended in a collagen solution were entrapped after collagen gelation and proliferated independent of the peptide modification of the hydrogel. Hydrogel modification with RGD peptide was sufficient to allow for the adhesion and differentiation of MSCs to the osteoblastic phenotype in the presence of osteogenic culture supplements. MSCs seeded with a collagen gel onto RGD-modified macroporous hydrogels after 28 days of culture showed a significant increase in cell numbers, from 15,200 +/- 2,000 to 208,600 +/- 69,700 cells (p < 0.05). Moreover, significant calcium deposition was apparent after 28 days of culture in RGD-modified hydrogels for cells suspended in a collagen gel in comparison to cells suspended in media, 3.47 +/- 0.26 compared to 0.82 +/- 0.20 mg Ca(2+) per scaffold (p < 0.05). Confocal microscopy revealed that MSCs suspended in a collagen gel and cultured on RGD-modified hydrogels for 28 days were adhered to the surface of the hydrogel while MSCs suspended in a collagen gel and cultured on unmodified hydrogels were located within the pores of and not in direct contact with the hydrogel surface. The results demonstrate that these biomimetic hydrogels facilitate the adhesion and support the differentiation of MSCs to the osteoblastic phenotype in the presence of osteogenic culture media.

Alkaline Phosphatase↗
PubMed2003

Protein adsorption and smooth muscle cell adhesion on biodegradable agmatine-modified poly(propylene fumarate-co-ethylene glycol) hydrogels.

We synthesized positively charged biodegradable hydrogels from poly(propylene fumarate-co-ethylene glycol) block copolymer and agmatine-modified poly(ethylene glycol)-tethered fumarate by radical crosslinking, and investigated the effect of the guanidino group of agmatine on vascular smooth muscle cell adhesion and protein adsorption to the hydrogels. In the presence of serum, the number of adherent smooth muscle cells per unit surface area increased dose-dependently from 15 to 75% of the initial seeding density at 20 h as the initial agmatine-modified monomer content increased from 0 to 200 mg/g. Cell spreading also depended on the initial monomer content. In the absence of serum, the number of adherent cells per unit surface area increased slightly from 10 to 17% of the initial seeding density as the initial monomer content increased from 0 to 200 mg/g. Cell adhesion increased significantly by adding exogenous vitronectin to serum-free medium, whereas exogenous fibronectin addition did not enhance cell adhesion. The enzyme-linked immunosorbent assay of fibronectin and vitronectin adsorbed onto the hydrogels revealed that the incorporation of positive charges into the hydrogels enhanced vitronectin, but not fibronectin, adsorption significantly. These results suggest that the guanidino group of agmatine enhanced cell adhesion by promoting the adsorption of serum components, and vitronectin may be one of the components.

Agmatine↗
PubMed1984

A model for the structure of fumarate reductase in the cytoplasmic membrane of Escherichia coli.

By a recombinant DNA approach we have prepared Escherichia coli cytoplasmic membranes that are highly enriched in the terminal electron transfer enzyme fumarate reductase. This enzyme is composed of four nonidentical subunits in equal molar ratio. A 69,000-dalton covalent flavin-containing subunit and a 27,000-dalton nonheme iron-containing subunit make up a membrane extrinsic catalytic domain. Two very hydrophobic subunits of 15,000 and 13,000 daltons make up the hydrophobic membrane anchor domain. Electron microscopy of negatively stained membranes shows a characteristic knob-and-stalk-type structure composed of the catalytic domain. The anchor polypeptides have been analyzed for hydrophobic segments and alpha-helical content and a model for their organization within the lipid bilayer is presented. The results reviewed in this paper suggest a model for the fumarate reductase complex in the cytoplasmic membrane.

Bacterial Proteins↗
PubMed1997

Structural characterization of human hemoglobin crosslinked by bis(3,5-dibromosalicyl) fumarate using mass spectrometric techniques.

Diaspirin crosslinked hemoglobin (DCLHb) was analyzed by mass spectrometric-based techniques to identify the protein modifications effected by the crosslinking reaction with bis(3,5-dibromosalicyl) fumarate. DCLHb consists of two principal components. These components were isolated by size-exclusion chromatography and identified by measurement of their molecular weight using electrospray mass spectrometry and subsequent peptide mass mapping and mass spectrometric sequence analysis of their individual digests. Three major RP-HPLC fractions were observed from the major hemoglobin in DCLHb. Their MWs matched the MW of heme, intact hemoglobin beta-chain, and two hemoglobin alpha-chains crosslinked by a fumarate moiety, respectively. The minor HPLC peaks of DCLHb were also separated, and characterized by mass spectrometric methods. These minor components revealed additional details of the structural nature of covalent modification of DCLHb.

Amino Acid Sequence↗
PubMed2000

Fumarate reductase is essential for Helicobacter pylori colonization of the mouse stomach.

Fumarate reductase (FRD) is the key enzyme in fumarate respiration induced by anaerobic growth of bacteria. In Helicobacter pylori, this enzyme appears to be constitutively expressed under microaerobic conditions and is not essential for its survival in vitro. In this study, the role of FRD in the colonization of H. pylori was investigated using a mouse model. The frdA gene coding for subunit A of FRD, and two control genes, copA and copP associated with the export of copper out of H. pylori, were inactivated by insertion of the chloramphenicol acetyltransferase cassette into these individual genes. The isogenic mutants of H. pylori strain AH244 were obtained by natural transformation. Seventy-five ICR mice (15 mice/group) were orogastrically dosed with either the wild type H. pylori strain AH244, its isogenic mutants, or Brucella broth (negative control). Five mice from each group were killed at 2, 4 and 8 weeks post-inoculation (WPI), respectively. H. pylori colonization was not detected in mouse gastric mucosa infected with the frdA mutant at any time point in the study by both quantitative culture and PCR. In contrast, the mice inoculated with either wild type AH244, copA or copPH. pylori mutants became readily infected. These data indicate that FRD plays a crucial role in H. pylori survival in the gastric mucosa of mice. Given that FRD, present in all H. pylori strains, is immunogenic in H. pylori -infected patients and H. pylori growth in vitro can be inhibited by three anthelmintics (morantel, oxantel and thiabendazole), this enzyme could potentially be used both as a novel drug target as well as in the development of vaccines for H. pylori prevention and eradication.

Animals↗
PubMed1990

The fumarate reductase operon of Wolinella succinogenes. Sequence and expression of the frdA and frdB genes.

The genes of the fumarate reductase of Wolinella succinogenes are organized in an operon. The three structural genes in the order frdC, frdA, frdB, are preceded by a common promoter (Körtner et al. 1990) and followed by a terminator of transcription. The proteins encoded by the genes are identical with the subunits present in the isolated enzyme. FrdA and FrdB are hydrophilic proteins consisting of 656 and 238 amino acids, respectively. The 12 cysteine residues present in FrdB form 3 ferredoxin-like clusters, whereas the 12 cysteines of FrdA are not clustered. Expression of FrdA and FrdB in Escherichia coli from a plasmid containing a DNA fragment with both genes in full length, gave rise to the EPR signals of the bi- and trinuclear iron-sulfur centers of the enzyme. Only the binuclear center was seen on the expression of FrdB together with a C-terminal fragment of FrdA (130 amino acid residues). Neither of the two centers was detected on the expression of FrdA together with a N-terminal fragment of FrdB including cysteine cluster I. Sequence comparison of FrdA and FrdB with the corresponding subunits of the fumarate reductases of E. coli or Proteus vulgaris or to those of the succinate dehydrogenases of E. coli or Bacillus subtilis revealed strong homologies (28-36% identical amino acid residues). Part of the homologous peptide stretches could be assigned to domains that are involved in the binding of the substrate of the FAD prosthetic group of the enzyme.

Amino Acid Sequence↗
PubMed1984

The fumarate reductase system as a site of anthelmintic attack in Ascaris suum.

Various benzimidazole compounds have been shown to be highly effective as inhibitors (up to 50% reduction of activity) in vitro of the helminth-specific enzyme, fumarate reductase, of Ascaris suum. Anthelmintically active and inactive benzimidazoles were similarly effective as inhibitors of enzyme activity. Albendazole-induced inhibition of fumarate reductase was not observed when the enzyme was preincubated with NADH.

Animals↗
PubMedDate not supplied

Ocular tolerability and safety of ketotifen fumarate ophthalmic solution.

Ketotifen fumarate, formulated for the treatment of allergic conjunctivitis, is a histamine H1-receptor antagonist, mast cell stabilizer, and eosinophil inhibitor (decreases chemotaxis and activation of eosinophils). In this study, healthy volunteers 3 years of age or older received ketotifen fumarate .025% ophthalmic solution (n = 330) or placebo (n = 165) four times daily for 6 weeks. Ketotifen was safe and well tolerated in the adult and pediatric populations, with an incidence of ocular adverse events of 18.2%, compared with 15.2% with placebo. No ocular rebound vasodilation or itching was observed within 48 hours after treatment. Ketotifen has a favorable safety and tolerability profile, which may have a positive impact on compliance, an important aspect of effective symptomatic control of allergic conjunctivitis.

Adult↗