A new series of isoxazole tethered quinone-amino acid hybrids has been designed and synthesized involving 1,3-dipolar cycloaddition reaction followed by an oxidation reaction using cerium ammonium nitrate (CAN). Using this method, for the first time various isoxazole tethered quinone-phenyl alanine and quinone-alanine hybrids were synthesized from simple commercially available 4-bromobenzyl bro...

FQR1 is a novel primary auxin-response gene that codes for a flavin mononucleotide-binding flavodoxin-like quinone reductase. Accumulation of FQR1 mRNA begins within 10 min of indole-3-acetic acid application and reaches a maximum of approximately 10-fold induction 30 min after treatment. This increase in FQR1 mRNA abundance is not diminished by the protein synthesis inhibitor cycloheximide, de...

A sulfhydryl-arylating quinone from the mushroom Agaricus bisporus, with an absorption maximum at 490 nm, was demonstrated to inhibit DNA polymerase a purified from calf thymus. The "490 quinone" could be generated through tyrosinase-mediated oxidation of y-i-glutaminyl4-hydroxybenzene or y-u-glutammyl-3,4-dihydroxybenzene. However, when y-L-glutaminyl-3,4-dihydroxybenzene was oxidized to y-L-g...

White, David C. (University of Kentucky College of Medicine, Lexington). Synthesis of 2-demethyl vitamin K(2) and the cytochrome system in Haemophilus. J. Bacteriol. 89:299-305. 1965.-The synthesis of the respiratory quinone, 2-demethyl vitamin K(2), is stimulated in Haemophilus parainfluenzae under conditions which provoke the synthesis of the cytochrome system. However, the various components...

There is a clear association between excessive exposure to estrogens and the development of cancer in several tissues including breast and endometrium. The risk factors for women developing these cancers are all associated with longer estrogen exposure, as may be facilitated by early menses, late menopause and long-term estrogen replacement therapy. Equilenin (1,3,5(10),6,8-estrapentaen-3-ol-17...

Amides are important compounds in organic synthesis and have significant roles pharmaceuticals, agrochemicals, materials. The Ritter reaction is a classical transformation to amides between nitriles alcohol derivatives or olefins. para-Quinone methides (p-QMs) highly reactive intermediates synthesis. cover picture visualizes that, as new acceptors, para-quinone joining the alcohols alkenes, kno...

A sulfhydryl-arylating quinone from the mushroom Agaricus bisporus, with an absorption maximum at 490 nm, was demonstrated to inhibit DNA polymerase a purified from calf thymus. The "490 quinone" could be generated through tyrosinase-mediated oxidation of y-i-glutaminyl4-hydroxybenzene or y-u-glutammyl-3,4-dihydroxybenzene. However, when y-L-glutaminyl-3,4-dihydroxybenzene was oxidized to y-L-g...

The metabolism of quinone-containing antitumor agents involves enzymatic reduction of the quinone by one or two electrons. This reduction results in the formation of the semiquinone or the hydroquinone of the anticancer drug. The consequence of these enzymatic reductions is that the semiquinone yields its extra electron to oxygen with the formation of superoxide radical anion and the original q...

The chemical oxidation and reduction processes of deprotonated, direduced o-quinone-exTTF-o-quinone in protic solvents were studied by EPR spectroscopy. The formation of relatively stable paramagnetic protonated redox forms of the parent triad was very surprising. The character of spin-density distribution in the semiquinone-quinone and semiquinone-catechol redox forms indicates that the p-phen...

Leucyl-tRNA synthetase from Escherichia coli is rapidly inactivated by 6-amino-7-chloro-5,8-dioxoquinoline (quinone), a model substance for cytostatic quinones. Loss of activity follows pseudo-first order kinetics. The quinone masks essential--SH groups that are reactive with N-ethylmaleimide. Specific protection of the enzyme by leucine provides evidence for active site-directed modification. ...