نتایج جستجو برای: catechols

تعداد نتایج: 714  

Journal: :Organic & biomolecular chemistry 2009
Oraphin Chantarasriwong Woo Cheal Cho Ayse Batova Warinthorn Chavasiri Curtis Moore Arnold L Rheingold Emmanuel A Theodorakis

The combination of unique structure and potent bioactivity exhibited by several family members of the caged Garcinia xanthones, led us to evaluate their pharmacophore. We have developed a Pd(0)-catalyzed method for the reverse prenylation of catechols that, together with a Claisen/Diels-Alder reaction cascade, provides rapid and efficient access to various caged analogues. Evaluation of the gro...

Journal: :Clinical chemistry 1990
R N Gupta

In this relatively simple procedure for extracting metanephrines from urine, after an internal standard (4-hydroxy-3-methoxybenzylamine in 1 mmol/L HCl) is added, the sample is hydrolyzed in a boiling water bath, then treated with ammonia and alumina. Excess ammonia is removed under reduced pressure and the sample is applied to a 1-mL Bond Elut SCX column, which is washed, and metanephrines and...

Journal: :Infection and immunity 1978
P V Liu F Shokrani

Strains of Pseudomonas aeruginosa able to grow readily in serum (serum resistant) produce siderophores in large quantity, enabling them to extract iron from transferrins. The term pyochelin has been proposed for this group of compounds. Pyochelin extractable with ethyl acetate and designated pyochelin A appears to be a mixture of catechols and other phenolates. The structures of water-soluble s...

Journal: :Applied microbiology 1967
J M Bollag C S Helling M Alexander

A microorganism capable of degrading 4-chloro-2-methylphenoxyacetic acid (MCPA) was isolated from soil and identified as Flavobacterium peregrinum. All of the chlorine of MCPA was released as chloride, and the carboxyl-carbon was converted to volatile products by growing cultures of the bacterium, but a phenol accumulated in the medium. The phenol was identified as 4-chloro-2-methylphenol on th...

Journal: :Acta biochimica Polonica 2011
Danuta Wojcieszyńska Izabela Greń Katarzyna Hupert-Kocurek Urszula Guzik

The purpose of this study was purification and characterization of phenol monooxygenase from Stenotrophomonas maltophilia strain KB2, enzyme that catabolises phenol and its derivatives through the initial hydroxylation to catechols. The enzyme requires NADH and FAD as a cofactors for activity, catalyses hydroxylation of a wide range of monocyclic phenols, aromatic acids and dihydroxylated deri...

Journal: :Advanced Functional Materials 2021

Reduction–oxidation (redox) reactions provide a distinct modality for biological communication that is fundamentally different from the more-familiar ion-based electrical modality. Biology uses these two modalities through systems (immune versus nervous), and mechanisms to control flow of charge carriers: soluble ions controlled using structural barriers (i.e., membranes) gates (e.g., membrane-...

Journal: :Science 2005
Liviu M Mirica Michael Vance Deanne Jackson Rudd Britt Hedman Keith O Hodgson Edward I Solomon T Daniel P Stack

The binuclear copper enzyme tyrosinase activates O2 to form a mu-eta2:eta2-peroxodicopper(II) complex, which oxidizes phenols to catechols. Here, a synthetic mu-eta2:eta2-peroxodicopper(II) complex, with an absorption spectrum similar to that of the enzymatic active oxidant, is reported to rapidly hydroxylate phenolates at -80 degrees C. Upon phenolate addition at extreme temperature in solutio...

Journal: :The Journal of biological chemistry 1989
B Kalyanaraman R C Sealy J G Liehr

Electron spin resonance spectroscopy has been used to detect, characterize, and to infer structures of o-semiquinones derived from stilbene catechol estrogens. Radicals were generated enzymatically using tyrosinase and were detected as their Mg2+ complexes. It is suggested that initial hydroxylation of stilbene estrogen gives a catechol estrogen in situ; subsequent two-electron oxidation of the...

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