نتایج جستجو برای: catechols
تعداد نتایج: 714 فیلتر نتایج به سال:
Polyphenol oxidase (PPO) (monophenol, o-diphenol: oxygen oxidoreductase; EC 1.14.18.1) is a binuclear copper-cluster-containing monooxygenase ubiquitously present in biological systems (1, 2). PPO may be distinguished from the related oxidase laccase [p-diphenol:oxygen oxidoreductase; EC 1.10.3.2] by its substrate specificity and the type and number of catalytic coppers. PPO catalyzes the oxida...
The importance of 0-methylation of catecholamines and other catechols as a metabolic pathway has been amply shown (l-4). The isolation of “Substanz Y,” a p-O-methylcatechol derivative from beef adrenal glands (5), and the occurrence of p-o-methylcatechol derivatives in urine (6) are suggestive of p-o-methylation in viva. Previous studies (7) have shown that in vitro the enzyme 0-methyltransfera...
Gas chromatography–mass spectrometry and gas chromatography with electron-capture detection have been investigated for analysis of persistent chlorinated aromatic compounds in the aquatic environment. A range of polychlorinated veratroles, guaiacols, and catechols produced during pulp bleaching and during PCB degradation were derivatized with pentafluorobenzyl bromide to improve their chromatog...
The utilization of CO2 as a carbon source for organic synthesis meets the urgent demand for more sustainability in the production of chemicals. Herein, we report on the enzyme-catalyzed para-carboxylation of catechols, employing 3,4-dihydroxybenzoic acid decarboxylases (AroY) that belong to the UbiD enzyme family. Crystal structures and accompanying solution data confirmed that AroY utilizes th...
Microorganisms are key players in the global carbon cycle. In addition, it appears that most xenobiotic industrial chemicals can be degraded by microorganisms, either by a combination of cometabolic steps or by serving as growth substrate, leading to the mineralization of at least part of the molecule. Here, we present the principles of the microbial aerobic degradation of chloroaromatic compou...
Polymorphic catechol-O-methyltransferase (COMT) catalyzes the O-methylation of estrogen catechols. In a case-control study, we evaluated the association of the low-activity allele (COMT(Met)) with breast cancer risk. Compared to women with COMT(Val/Val), COMT(Met/Met) was associated with an increased risk among premenopausal women [odds ratio (OR), 2.1; confidence interval (CI), 1.4-4.3] but wa...
The major metabolites of epinephrine have been recently identified as the 0-methylated derivatives, 3-methoxy-4-hydroxymandelic acid (1)) metanephrine (2)) and 3-methoxy-4hydroxyphenylglycol (3). The corresponding catechols, 3,4dihydroxymandelic acid (4), 3,4-dihydroxyphenylglycol (5)) and epinephrine and its conjugates (6) were found to be minor excretion products. The present study was design...
Mussels attach to solid surfaces in the sea. Their adhesion must be rapid, strong, and tough, or else they will be dislodged and dashed to pieces by the next incoming wave. Given the dearth of synthetic adhesives for wet polar surfaces, much effort has been directed to characterizing and mimicking essential features of the adhesive chemistry practiced by mussels. Studies of these organisms have...
The enzyme which cleaves the benzene ring of 6-chlorohydroxyquinol was purified to apparent homogeneity from an extract of 2,4,6-trichlorophenol-grown cells of Streptomyces rochei 303. Like the analogous enzyme from Azotobacter sp. strain GP1, it exhibited a highly restricted substrate specificity and was able to cleave only 6-chlorohydroxyquinol and hydroxyquinol and not catechol, chlorinated ...
Both epinephrine and norepinephrine enhance the process of fat mobilization. This property of promoting lipolysis has been observed both in vitro by demonstrating the release of free fatty acids (FFA) and glycerol from adipose tissue within the medium, and in vivo by the increase in the levels of plasma FFA in the fasted, resting individual (1-3). It was the intent of this study to determine wh...
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