Selectivity of catechol O-methyltransferase has been examined for the three ring-fluorinated norepinephrines to elucidate the role of acidity of the phenolic groups in their methylation. Substitution of fluorine at the 5-position of norepinephrine reverses the selectivity of catechol O-methyltransferase so that p-O-methylation predominates. The 5-fluoro substituent also causes the pKa of the p-...

Catechols play an important role in many natural systems. They are known to readily interact with both organic (e.g., amino acids) and inorganic (e.g., metal ions, metal oxides) compounds, thereby providing a powerful system for protein curing. Catechol crosslinked protein networks, such as sclerotized cuticle and byssal threads of the mussel, have been shown to exhibit excellent mechanical pro...

Eighteen 4-t-octylphenol-degrading bacteria were isolated and screened for the presence of degradative genes by polymerase chain reaction method using four designed primer sets. The primer sets were designed to amplify specific fragments from multicomponent phenol hydroxylase, single component monooxygenase, catechol 1,2-dioxygenase and catechol 2,3-dioxygenase genes. Seventeen of the 18 isolat...

The catalytic oxidation of catechol by crude preparations of mushroom tyrosinase was studied by a method yielding data on initial reaction velocities. Graphical analysis of the results suggests that an excess of catechol inhibits its own oxidation by a competitive process, thus accounting for the observed optimum in the substrate concentration. However, added phenol, though itself a substrate, ...

in chemotherapy. Recently there are manyreports detailing with /Mactams containing the catechol moiety1~5). In addition, it has also been reported that the introduction of a monoor dihydroxypyridone moiety6~ 12) instead of a catechol group as an isostere is effective in improving stability against catechol-0-methyltransferase (COMT)6). Such compounds show marked activity against Gramnegative or...

BACKGROUND Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsi...

Catechol estrogens are considered critical intermediates in estrogen-induced carcinogenesis. We demonstrated previously that 17beta-estradiol (E(2)), estrone (E(1)) and four of their catechol estrogens, 2- and 4-hydroxyestradiols (2- and 4-OHE(2)), and 2- and 4-hydroxyestrones (2- and 4-OHE(1)) induce morphological transformation in Syrian hamster embryo (SHE) fibroblasts, and the transforming ...

abstract kinetic properties of root of peroxidase of gundelia tournefortii investigated at different ph, temperature and different inhibitors. maximum activity of peroxidase achieved at ph 5.5-6 in according to type of substrate. activity of peroxidase increased at constant concentration of h2o2 and different concentration of guaiacol, catechol and pyrogallol. the maximum activity in presence o...

1. Erythrocyte catechol-O-methyltransferase was studied in a population sample of 147 subjects. 2. There was a wide interindividual variability of catechol-O-methyltransferase activity, which was not unimodally distributed. Catechol-O-methyltransferase activity was not influenced by blood pressure, age or sex, nor was it related to plasma noradrenaline or urinary catecholamines or metanephrines...

The accompanying diagram illustrates a mechanism proposed for the enzymic oxidation of catechol (l-5). In the present study the oxidations of catechol and hydroxyhydroquinone at varying concentrations of substrate, enzyme, and hydrogen ion have been followed spectrophotometrically. Step 1, first proposed by Raper on chemical grounds (6), has been confirmed. Further results indicate that the cat...