Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Five selenium compounds, Na2Se04, H2Se04, Na2Se03, H2Se03 and Se02, were tested for their capacity to induce chromosome aberrations in cultured human leukocytes and for their reactivity with DNA by a rec-assay system and inactivation of transforming activity in Bacillus subtilis. Chromosome-breaking activity was significantly higher for the compounds with four-valent than with six-valent selenium, the efficiency being in the decreasing order H2S03 greater than Na2Se03 greater than Se02 greater than H2Se04 greater than Na2Se04. Rec assay using B. subtilis with different recombination capacities suggested that damage to DNA was produced by selenites but not by selenates. The reactivity of selenites with DNA was also indicated by a significant loss of transformation of the tryptophan marker of B. subtilis DNA treated with H2Se03 and Se02.
 ...
PMID:Studies on selenium-related compounds. V. Cytogenetic effect and reactivity with DNA. 0 4

Near-ultraviolet (300 to 400 nm) irradiation of L-tryptophan yielded H2O2 (a toxic photoproduct) that was selectively lethal for rec and polA1 Escherichia coli mutants. H2O2 treatment of cells resulted in the induction of single-strand deoxyribonucleic acid breaks. These breaks were repaired to only a small extent in polA1, recA recB, and recA mutants, but were efficiently repaired in wild-type strains. We conclude that H2O2 deoxyribonucleic acid lesions require both the polA+ and recA+ pathways for repair.
 ...
PMID:Repair of hydrogen peroxide-induced single-strand breaks in Escherichia coli deoxyribonucleic acid. 32 27

It was confirmed by the procedure of rec-assay that DNA-damaging activities were formed in the reaction systems containing nitrite and phenol derivatives including BHA, tryptophan or cysteine under gastric pH conditions. The mutagenic action of the nitrite-BHA, nitrite-tryptophan and nitrite-cysteine systems was also tested according to Ames' method using Salmonella typhimurium TA 1535 and TA 98. The mutagenic activity was observed in the nitrite-tryptophan and nitrite-cysteine systems, though the nitrite-BHA system did not show the activity. The DNA-damaging products were generally labile, i.e., the activity decreased significantly after 1.5 to 2 hours of the reaction, except in the case of the nitrite-BHA system. The DNA-damaging activity in the nitrite-BHA system did not decrease even after 48 hours of the reaction. Nitrosophenol derivatives themselves showed the DNA-damaging activity at pH 1. The active product in the nitrite-BHA system was isolated and the structure was determined to be 2-tert-butyl-quinone. This compound gave a positive rec-assay test, and showed no mutagenesis by Ames' method. The active product from the nitrite-cysteine system was infered to be nitrosocysteine, and the product showed both DNA-damaging and mutagenic activity.
 ...
PMID:Formation of DNA-damaging and mutagenic activity in the reaction systems containing nitrite and butylated hydroxyanisole, tryptophan, or cysteine. 39 55

The incorporation of 3H-tryptophan into the inner enamel epithelium of newborn mouse incisor tooth organs has been studied in situ by light and electron microscopic autoradiography to determine the sites and kinetics of biosynthesis, migration, and secretion of precursor enamel protein during newborn mouse incisor tooth formation maxillary and mandibular incisor tooth amelogenesis was studied 5, 30, 60, 120, 240 minutes and 24 hours following the intraperitoneal injection of 3H-tryptophan. By 5 minutes, 40% of the total silver grains associated with the secretory ameloblasts were localized over the rough endoplasmic reticulum and 50% of the silver grains were localized over the Golgi apparatus. By 30 minutes, silver grains were observed predominately over condensing vacuoles and secretory granules within the forming Tomes' processes, and were also localized over the extracellular "granular" pre-enamel matrix. The enamel proteins were synthesized on membrane-bound polysomes, transferred within the cisternae of the rough endoplasmic reticulum and then accumulated in the inner saccules of the Golgi apparatus. The enamel proteins were than packaged in condensing vacuoles which subsequently became secretory granules which migrated to the lateral and apical secretory regions of the forming Tomes' processes. It was concluded from these in vivo studies that enamel protein were synthesized and subsequently secreted within 30 minutes. The initially secreted precursor enamel protein was localized over a material which demonstrated a granular or stippled ultrastructure. The labeled protein then was localized over the amorphous enamel matrix per se which contained the forming calcium hydroxyapatite crystals. We assumed, therefore, that there are two different ultrastructural forms of 3H-tryptophan containing extracellular enamel proteins and suggest that the granular or "stippled" form represents newly secreted precursor enamel protein.
Anat Rec 1976 Jul
PMID:The biosynthesis and secretion of precursor enamel protein by ameloblasts as visualized by autoradiography after tryptophan administration. 93 36

The reaction products from L-tryptophan treated with nitrite under acidic conditions were investigated for mutagenic activity with the Salmonella typhimurium his reversion assay and for DNA-damaging activity using the rec-assay. The diethyl ether extract of the reaction mixture showed 8 spots on thin-layer chromatography (TLC). One compound from the TLC had high mutagenic activity for TA98 without S9 mix, with little DNA-damaging activity. The mutagen was purified and identified by instrumental analysis as 2-hydroxy-(1-N-nitrosoindole)propionic acid (NIHP). The mutagenic activity of NIHP was determined by the induced mutation frequency method; the induced mutation frequency was about 19.2 X 10(-5) at a dose level of 160 micrograms/plate.
 ...
PMID:Mutagen formed from tryptophan reacted with sodium nitrite in acidic solution. 304 38

Indole and 3-methylindole (3MI) are ruminal metabolites of L-tryptophan (TRP) and have similar physical and chemical properties. 3-Methylindole causes acute bovine pulmonary emphysema (ABPE). The effects of indole when administered orally to cows were determined. Four mature Holstein cows were given increasing doses of 0.05, 0.1 and 0.2 g indole per kg body-weight orally at two-week intervals. The animals were killed one week after the last dose. Plasma indole concentrations peaked three house after administration at 4.5, 8.8 and 19.8 microgram per ml after the 0.05, 0.1 and 0.2 doses, respectively. Detectable concentrations of indole (more than 0.02 microgram per ml) persisted in the plasma from three to 25 hours after dosing. Packed cell volume was decreased (P less than 0.01) at 48 and 72 hours after the 0.2 g per kg dose and at 72 hours after the 0.1 g per kg dose. Plasma haemoglobin was increased (P less than 0.05) at 48 hours after the 0.2 and 0.1 g per kg doses. By 72 hours after the 0.2 g per kg dose, all cows had mild diarrhoea and haemolysis and two of the cows had haemoglobinuria. At necropsy, microscopic lesions of haemoglobinuric nephrosis were seen in all four cows. No lesions of ABPE were found in any of the animals.
Vet Rec 1980 Oct 11
PMID:Indole toxicity in cattle. 721 Apr 36

The pathogenesis of acute bovine pulmonary oedema and emphysema (ABPE) is related to the ruminal formation of 3-methylindole (3MI) from L-tryptophan (TRP), a naturally occurring amino acid and constituent of forage. The objectives of the present study were to determine whether monensin and lasalocid, both polyether antibiotics, were effective in reducing ruminal conversion of TRP to 3MI in vivo and to confirm that reduction in ruminal conversion of TRP to 3MI prevented tryptophan induced ABPE. Sixteen mature Hereford cows were assigned to one of four groups and given TRP to induce ABPE. Group 1 was given 100 mg monensin orally twice daily starting one day before and ending four days after TRP dosing. Group 2 was given 200 mg monensin once daily and group 3 was given 100 mg lasalocid twice daily. Group 4, the control, was given only TRP without further treatment. All control cows developed clinical signs of respiratory disease and lesions of ABPE; one control cow died of ABPE. Mean ruminal 3MI concentrations in control cows reached a peak of 36.4 micrograms per ml. Clinical signs of pulmonary disease appeared in two cows treated with lasalocid and one died. Mean ruminal 3MI in these animals peaked at 38.8 micrograms per ml. No clinical signs of respiratory disease were observed in any of the monensin treated cows and at necropsy there were no pulmonary lesions of ABPE. Mean ruminal 3MI concentrations in monensin treated cows did not exceed 8.9 micrograms per ml. In all groups plasma 3MI concentrations generally reflected ruminal 3MI concentrations but at lower concentrations. The results of this experiment demonstrate that reduction in ruminal 3MI formation by monensin prevents tryptophan induced ABPE.
Vet Rec 1980 Oct 04
PMID:Prevention of tryptophan-induced acute bovine pulmonary oedema and emphysema (fog fever). 746 89

The mitochondrial outer membrane enzyme kynurenine 3-hydroxylase (K3H) is an NADPH-dependent flavin mono-oxygenase involved in the tryptophan pathway, where it catalyzes the hydroxylation of kynurenine. K3H was transiently expressed in COS-1 cells as a glutathione S-transferase (GST) fusion protein, and the pure recombinant protein (rec-K3H) was obtained with a specific activity of about 2000 nmol.min-1.mg-1. Rec-K3H was shown to have an optimum pH at 7.5, to use NADPH more efficiently than NADH, and to contain one molecule of non-covalently bound FAD per molecule of enzyme. The mechanism of the rec-K3H-catalyzed reaction was investigated by overall initial-rate measurements, and a random mechanism in which combination of the enzyme with one substrate does not influence its affinity for the other is proposed. Further kinetic studies revealed that K3H activity was inhibited by both pyridoxal phosphate and Cl-, and that NADPH-catalyzed oxidation occurred even in the absence of kynurenine if 3-hydroxykynurenine was present, suggesting an uncoupling effect of 3-hydroxykynurenine with peroxide formation. This observation could be of clinical interest, as peroxide formation could explain the neurotoxicity of 3-hydroxykynurenine in vivo.
 ...
PMID:Functional characterization and mechanism of action of recombinant human kynurenine 3-hydroxylase. 1067 18

Tryptophan synthase is a classic enzyme that channels a metabolic intermediate, indole. The crystal structure of the tryptophan synthase alpha2beta2 complex from Salmonella typhimurium revealed for the first time the architecture of a multienzyme complex and the presence of an intramolecular tunnel. This remarkable hydrophobic tunnel provides a likely passageway for indole from the active site of the alpha subunit, where it is produced, to the active site of the beta subunit, where it reacts with L-serine to form L-tryptophan in a pyridoxal phosphate-dependent reaction. Rapid kinetic studies of the wild type enzyme and of channel-impaired mutant enzymes provide strong evidence for the proposed channeling mechanism. Structures of a series of enzyme-substrate intermediates at the alpha and beta active sites are elucidating enzyme mechanisms and dynamics. These structural results are providing a fascinating picture of loops opening and closing, of domain movements, and of conformational changes in the indole tunnel. Solution studies provide further evidence for ligand-induced conformational changes that send signals between the alpha and beta subunits. The combined results show that the switching of the enzyme between open and closed conformations couples the catalytic reactions at the alpha and beta active sites and prevents the escape of indole.
Chem Rec 2001
PMID:Tryptophan synthase: a multienzyme complex with an intramolecular tunnel. 1189 63

Concentrations of tryptophan (TRP) and serotonin (5-HT) in plasma were measured in 36 moderately trained Dutch warmblood horses after eight weeks on a high fibre (n=18) or high starch (n=18) diet. Samples were taken three hours after feeding, when the horse was at rest, either at 11.00 or 14.00 hours. Plasma 5-HT and pH were significantly higher in horses fed a high fibre diet than those fed a high starch diet (P<0.05 and P<0.01, respectively), and significantly higher levels of TRP were found in mares than geldings (P<0.05). Plasma 5-HT may therefore be a good marker of serotonergic activity.
Vet Rec 2010 Jan 30
PMID:Effect of diet on plasma tryptophan and serotonin in trained mares and geldings. 2011 69


1 2 Next >>