indolequinones

Summary

Summary: INDOLES which have two keto groups forming QUINONES like structures of the indole aromatic ring.

Top Publications

  1. Phillips R, Naylor M, Jaffar M, Doughty S, Everett S, Breen A, et al. Bioreductive activation of a series of indolequinones by human DT-diaphorase: structure-activity relationships. J Med Chem. 1999;42:4071-80 pubmed
    A series of indolequinones including derivatives of EO9 bearing various functional groups and related indole-2-carboxamides have been studied with a view to identifying molecular features which confer substrate specificity for purified ..
  2. Setzer W, Holland M, Bozeman C, Rozmus G, Setzer M, Moriarity D, et al. Isolation and frontier molecular orbital investigation of bioactive quinone-methide triterpenoids from the bark of Salacia petenensis. Planta Med. 2001;67:65-9 pubmed
  3. van der Heijden A, Verhaegh G, Jansen C, Schalken J, Witjes J. Effect of hyperthermia on the cytotoxicity of 4 chemotherapeutic agents currently used for the treatment of transitional cell carcinoma of the bladder: an in vitro study. J Urol. 2005;173:1375-80 pubmed
    ..Hyperthermia alone did not cause decreased cell proliferation. Synergism was most prominent with low drug doses and the most potent drug used in this in vitro study was EO9. ..
  4. Phillips R, Hulbert P, Bibby M, Sleigh N, Double J. In vitro activity of the novel indoloquinone EO-9 and the influence of pH on cytotoxicity. Br J Cancer. 1992;65:359-64 pubmed
    ..6 ug ml-1 respectively). These studies suggest that if EO-9 can be delivered to regions of low pH within solid tumours, a therapeutic advantage may be obtained. ..
  5. Puri R, Palit V, Loadman P, Flannigan M, Shah T, Choudry G, et al. Phase I/II pilot study of intravesical apaziquone (EO9) for superficial bladder cancer. J Urol. 2006;176:1344-8 pubmed
    ..Intravesical administration of 4 mg/40 ml apaziquone was well tolerated and had ablative activity against superficial bladder cancer marker lesions. ..
  6. van der Heijden A, Moonen P, Cornel E, Vergunst H, de Reijke T, van Boven E, et al. Phase II marker lesion study with intravesical instillation of apaziquone for superficial bladder cancer: toxicity and marker response. J Urol. 2006;176:1349-53; discussion 1353 pubmed
    ..Local side effects were comparable to side effects due to other chemotherapy instillations. ..
  7. Wen B, Chen Y, Fitch W. Metabolic activation of nevirapine in human liver microsomes: dehydrogenation and inactivation of cytochrome P450 3A4. Drug Metab Dispos. 2009;37:1557-62 pubmed publisher
    ..029 min(-1), respectively. It is proposed that formation of the quinone methide intermediate may represent a rate-limiting step in the initiation of nevirapine-mediated hepatotoxicity...
  8. Kim D, Shin E, Kim Y, Lee B, Jun J, Park J, et al. Suppression of inflammatory responses by celastrol, a quinone methide triterpenoid isolated from Celastrus regelii. Eur J Clin Invest. 2009;39:819-27 pubmed publisher
    ..Our data suggest that celastrol inhibits the production of inflammatory mediators and is a potential target for the treatment of various inflammatory diseases. ..
  9. Deng P, Zhong D, Nan F, Liu S, Li D, Yuan T, et al. Evidence for the bioactivation of 4-nonylphenol to quinone methide and ortho-benzoquinone metabolites in human liver microsomes. Chem Res Toxicol. 2010;23:1617-28 pubmed publisher
    ..The findings of the quinone methide and benzoquinone metabolites intensified the concern on the impact of 4-NP exposure on human health. ..

More Information

Publications108 found, 100 shown here

  1. Veldhuyzen W, Lam Y, Rokita S. 2'-Deoxyguanosine reacts with a model quinone methide at multiple sites. Chem Res Toxicol. 2001;14:1345-51 pubmed
    ..8:3.2:1.0 for adducts of N(2):N7:N1) relative to that of dG (4.7:3.5:1.0 for adducts of N(2):N7:N1). ..
  2. Reigan P, Colucci M, Siegel D, Chilloux A, Moody C, Ross D. Development of indolequinone mechanism-based inhibitors of NAD(P)H:quinone oxidoreductase 1 (NQO1): NQO1 inhibition and growth inhibitory activity in human pancreatic MIA PaCa-2 cancer cells. Biochemistry. 2007;46:5941-50 pubmed
    ..In this report, we describe a series of indolequinones, based on 5-methoxy-1,2-dimethyl-3-[(4-nitrophenoxy)methyl]indole-4,7-dione (ES936), and evaluate NQO1 ..
  3. Dunlap T, Piyankarage S, Wijewickrama G, Abdul Hay S, Vanni M, LITOSH V, et al. Quinone-induced activation of Keap1/Nrf2 signaling by aspirin prodrugs masquerading as nitric oxide. Chem Res Toxicol. 2012;25:2725-36 pubmed publisher
    ..Current interest in electrophilic drugs acting via Nrf2 signaling suggests that QM-donating hybrid drugs can be designed as informative chemical probes in drug discovery. ..
  4. Freccero M, Di Valentin C, Sarzi Amadè M. Modeling H-bonding and solvent effects in the alkylation of pyrimidine bases by a prototype quinone methide: a DFT study. J Am Chem Soc. 2003;125:3544-53 pubmed
  5. Remião F, Rettori D, Han D, Carvalho F, Bastos M, Cadenas E. Leucoisoprenochrome-o-semiquinone formation in freshly isolated adult rat cardiomyocytes. Chem Res Toxicol. 2004;17:1584-90 pubmed
  6. Uzelac L, Škalamera Đ, Mlinarić Majerski K, Basarić N, Kralj M. Selective photocytotoxicity of anthrols on cancer stem-like cells: The effect of quinone methides or reactive oxygen species. Eur J Med Chem. 2017;137:558-574 pubmed publisher
  7. Amouri H, Le Bras J. Taming reactive phenol tautomers and o-quinone methides with transition metals: a structure-reactivity relationship. Acc Chem Res. 2002;35:501-10 pubmed
    ..This reaction was at the origin of the discovery of a general synthetic procedure to prepare the first metal-stabilized o-quinone methide. ..
  8. Paris I, Martinez Alvarado P, Cardenas S, Perez Pastene C, Graumann R, Fuentes P, et al. Dopamine-dependent iron toxicity in cells derived from rat hypothalamus. Chem Res Toxicol. 2005;18:415-9 pubmed
    ..These studies suggest that iron can induce cell toxicity by a mechanism that requires the formation and NET-mediated uptake of an Fe-dopamine complex, ultimately resulting in the intracellular formation of reactive species. ..
  9. Celli C, Tran N, Knox R, Jaiswal A. NRH:quinone oxidoreductase 2 (NQO2) catalyzes metabolic activation of quinones and anti-tumor drugs. Biochem Pharmacol. 2006;72:366-76 pubmed
    ..These results concluded that NQO2 plays a significant role in the metabolic activation of both quinones and anti-tumor drugs leading to cytotoxicity and cell death. ..
  10. Spence J, George J. Biomimetic total synthesis of ent-penilactone A and penilactone B. Org Lett. 2013;15:3891-3 pubmed publisher
  11. Batsomboon P, Phakhodee W, Ruchirawat S, Ploypradith P. Generation of ortho-quinone methides by p-TsOH on silica and their hetero-Diels-Alder reactions with styrenes. J Org Chem. 2009;74:4009-12 pubmed publisher
    ..The corresponding chromans were obtained in moderate to excellent yields (42-97%) and in moderate to excellent diastereoselectivity (up to >99:1). ..
  12. Nishihira J, Fujinaga M, Kuriyama T, Suzuki M, Sugimoto H, Nakagawa A, et al. Molecular cloning of human D-dopachrome tautomerase cDNA: N-terminal proline is essential for enzyme activation. Biochem Biophys Res Commun. 1998;243:538-44 pubmed
    ..Although the precise pathophysiological function of D-dopachrome tautomerase remains to be elucidated, the present results could contribute to further understanding of isomerase activity in relation to the immune response. ..
  13. Gligorich K, Schultz M, Sigman M. Palladium(II)-catalyzed aerobic hydroalkoxylation of styrenes containing a phenol. J Am Chem Soc. 2006;128:2794-5 pubmed
    ..This is followed by formation of a quinone methide and subsequent addition of an alcohol to yield the hydroalkoxylated product. ..
  14. Davidson V, Liu A. Tryptophan tryptophylquinone biosynthesis: a radical approach to posttranslational modification. Biochim Biophys Acta. 2012;1824:1299-305 pubmed publisher
    ..This article is part of a Special Issue entitled: Radical SAM enzymes and Radical Enzymology. ..
  15. Zhang M, Aman P, Grubb A, Panagopoulos I, Hindemith A, Rosengren E, et al. Cloning and sequencing of a cDNA encoding rat D-dopachrome tautomerase. FEBS Lett. 1995;373:203-6 pubmed
    ..A homology search in the EST database found a human cDNA encoding a peptide sharing 66% homology with the rat enzyme. The rat D-dopachrome tautomerase shares 27% homology with the rat macrophage migration inhibitory factor (MIF). ..
  16. Awad H, Boersma M, Boeren S, van der Woude H, van Zanden J, van Bladeren P, et al. Identification of o-quinone/quinone methide metabolites of quercetin in a cellular in vitro system. FEBS Lett. 2002;520:30-4 pubmed
  17. Paris I, Perez Pastene C, Cardenas S, Iturriaga Vasquez P, Iturra P, Munoz P, et al. Aminochrome induces disruption of actin, alpha-, and beta-tubulin cytoskeleton networks in substantia-nigra-derived cell line. Neurotox Res. 2010;18:82-92 pubmed publisher
    ..These results suggest that aminochrome one-electron metabolism induces the disruption of the normal morphology of actin, alpha-, and beta-tubulin in the cytoskeleton, and that DT-diaphorase prevents these effects. ..
  18. Sharma A, Santos I, Gaur P, Ferreira V, Garcia C, da Rocha D. Addition of thiols to o-quinone methide: new 2-hydroxy-3-phenylsulfanylmethyl[1,4]naphthoquinones and their activity against the human malaria parasite Plasmodium falciparum (3D7). Eur J Med Chem. 2013;59:48-53 pubmed publisher
    ..The new naphthoquinones obtained by this methodology were shown to have moderate to good in vitro antimalarial activity against Plasmodium falciparum (3D7). ..
  19. Chen S, Knox R, Lewis A, Friedlos F, Workman P, Deng P, et al. Catalytic properties of NAD(P)H:quinone acceptor oxidoreductase: study involving mouse, rat, human, and mouse-rat chimeric enzymes. Mol Pharmacol. 1995;47:934-9 pubmed
    ..Based on these results, we propose that the carboxyl-terminal portion of the enzyme plays an important role in the reduction of cytotoxic drugs and the binding of flavones. ..
  20. Phillips R, Loadman P, Cronin B. Evaluation of a novel in vitro assay for assessing drug penetration into avascular regions of tumours. Br J Cancer. 1998;77:2112-9 pubmed
    ..These results suggest that the failure of EO9 in the clinic is due to a combination of poor drug penetration and rapid elimination in vivo. ..
  21. Martinez Alvarado P, Dagnino Subiabre A, Paris I, Metodiewa D, Welch C, Olea Azar C, et al. Possible role of salsolinol quinone methide in the decrease of RCSN-3 cell survival. Biochem Biophys Res Commun. 2001;283:1069-76 pubmed
    ..Evidence of the formation of salsolinol o-semiquinone radical has been provided by ESR studies during one-electron oxidation of salsolinol catalyzed by lactoperoxidase. ..
  22. Le Gresley A, Gudivaka V, Carrington S, Sinclair A, Brown J. Synthesis, analysis and biological evaluation of novel indolquinonecryptolepine analogues as potential anti-tumour agents. Org Biomol Chem. 2016;14:3069-79 pubmed publisher
  23. Awad H, Boersma M, Boeren S, van Bladeren P, Vervoort J, Rietjens I. The regioselectivity of glutathione adduct formation with flavonoid quinone/quinone methides is pH-dependent. Chem Res Toxicol. 2002;15:343-51 pubmed
    ..Together the results of the present study elucidate the mechanism of the pH-dependent electrophilic behavior of B ring catechol flavonoids, which appears more straightforward than previously foreseen. ..
  24. Imai A, Yokoyama T, Matsumoto Y, Meshitsuka G. Significant lability of guaiacylglycerol beta-phenacyl ether under alkaline conditions. J Agric Food Chem. 2007;55:9043-6 pubmed
    ..This promotion of the quinone methide formation explains why a relatively large amount of 4-hydroxy-3-methoxybenzaldehyde (IV) is produced from I in an oxygen-alkali treatment. ..
  25. Huang S, Ting K, Wang K. Development of a long-wavelength fluorescent probe based on quinone-methide-type reaction to detect physiologically significant thiols. Anal Chim Acta. 2008;620:120-6 pubmed publisher
    ..This novel fluorimetric probe demonstrates a good relationship in detecting thiols in 1-100 microM range, which presents to the applicability for the construction of fiber-optic biosensors in the future clinical diagnostic. ..
  26. Khdour O, Skibo E. Quinone methide chemistry of prekinamycins: 13C-labeling, spectral global fitting and in vitro studies. Org Biomol Chem. 2009;7:2140-54 pubmed publisher
    ..We also prepared a stable quinone methide of prekinamycin and studied its solution chemistry directly. ..
  27. Husni A, Jeon J, Um B, Han N, Chung D. Tyrosinase inhibition by water and ethanol extracts of a far eastern sea cucumber, Stichopus japonicus. J Sci Food Agric. 2011;91:1541-7 pubmed publisher
    ..The sea cucumber extracts were demonstrated to possess considerable inhibitory potency against the diphenolase activity of tyrosinase, suggesting that the sea cucumber may be a good source of safe and effective tyrosinase inhibitors. ..
  28. Samuni A, DeGraff W, Krishna M, Mitchell J. Nitroxides as antioxidants: Tempol protects against EO9 cytotoxicity. Mol Cell Biochem. 2002;234-235:327-33 pubmed
    ..or detoxification of O2.- and H2O2. ..
  29. Ohguchi K, Akao Y, Nozawa Y. Involvement of calpain in melanogenesis of mouse B16 melanoma cells. Mol Cell Biochem. 2005;275:103-7 pubmed
    ..These results indicate that calpain would be involved in the melanogenic signaling by modulating the expression of tyrosinase in mouse B16 melanoma cells. ..
  30. Zhu H, Jia Z, Mahaney J, Ross D, Misra H, Trush M, et al. The highly expressed and inducible endogenous NAD(P)H:quinone oxidoreductase 1 in cardiovascular cells acts as a potential superoxide scavenger. Cardiovasc Toxicol. 2007;7:202-11 pubmed
    ..scavenging ability. Taken together, these results demonstrate that the highly expressed and inducible endogenous NQO1 in cardiovascular cells may act as a potential O2(.-) scavenger. ..
  31. Van der Schoot S, Vainchtein L, Nuijen B, Gore A, Mirejovsky D, Lenaz L, et al. Purity profile of the indoloquinone anticancer agent EO-9 and chemical stability of EO-9 freeze dried with 2-hydroxypropyl-beta-cyclodextrin. Pharmazie. 2008;63:796-805 pubmed
    ..Five, probably synthetic intermediates were found. However, the amount of total impurities was very small for both lots of drug substance and below acceptable international limits for pharmaceutical use. ..
  32. Aguirre P, Urrutia P, Tapia V, Villa M, Paris I, Segura Aguilar J, et al. The dopamine metabolite aminochrome inhibits mitochondrial complex I and modifies the expression of iron transporters DMT1 and FPN1. Biometals. 2012;25:795-803 pubmed publisher
    ..These results suggest that aminochrome is an endogenous toxin that inhibits by oxidative modifications mitochondrial complex I and modifies the levels of iron transporters in a way that leads to iron accumulation. ..
  33. Vandenberghe I, Kim J, Devreese B, Hacisalihoglu A, Iwabuki H, Okajima T, et al. The covalent structure of the small subunit from Pseudomonas putida amine dehydrogenase reveals the presence of three novel types of internal cross-linkages, all involving cysteine in a thioether bond. J Biol Chem. 2001;276:42923-31 pubmed publisher
    ..The thioether type bond in all four of these adducts has never been found in other proteins. CTQ is a novel cofactor in the series of the recently discovered quinone cofactors...
  34. Powell B, Baruah T, Bernstein N, Brake K, McKenzie R, Meredith P, et al. A first-principles density-functional calculation of the electronic and vibrational structure of the key melanin monomers. J Chem Phys. 2004;120:8608-15 pubmed
    ..It is hoped that this may be a helpful analytical tool in determining the structure of eumelanin macromolecules and hence in helping to determine the structure-property-function relationships that control the behavior of the eumelanins. ..
  35. Messina P, Labbé E, Buriez O, Hillard E, Vessieres A, Hamels D, et al. Deciphering the activation sequence of ferrociphenol anticancer drug candidates. Chemistry. 2012;18:6581-7 pubmed publisher
    ..The study revealed the passage from an iron-centered to a carbon-centered radical, which is then oxidized to yield the quinone methide, namely, the species that interacts with proteins and so forth under biological conditions. ..
  36. Baas P, Michielsen C, Oppelaar H, Van Zandwijk N, Stewart F. Enhancement of interstitial photodynamic therapy by mitomycin C and EO9 in a mouse tumour model. Int J Cancer. 1994;56:880-5 pubmed
    ..Factors such as PDT-induced hypoxia, pH changes, temperature increases and production of toxic reactive oxygen species by both drugs may play a role in the enhanced MMC cytotoxicity. ..
  37. Feng M, Jensen L, Yukl E, Wei X, Liu A, Wilmot C, et al. Proline 107 is a major determinant in maintaining the structure of the distal pocket and reactivity of the high-spin heme of MauG. Biochemistry. 2012;51:1598-606 pubmed publisher
  38. Linsenbardt A, Breckenridge J, Wilken G, Macarthur H. Dopaminochrome induces caspase-independent apoptosis in the mesencephalic cell line, MN9D. J Neurochem. 2012;122:175-84 pubmed publisher
  39. Sugumaran M, Duggaraju P, Jayachandran E, Kirk K. Formation of a new quinone methide intermediate during the oxidative transformation of 3,4-dihydroxyphenylacetic acids: implication for eumelanin biosynthesis. Arch Biochem Biophys. 1999;371:98-106 pubmed
    Oxidation of dopa and dopamine requires a net removal six electrons to produce indolequinones, the monomeric precursors of eumelanin pigment...
  40. Loadman P, Phillips R, Lim L, Bibby M. Pharmacological properties of a new aziridinylbenzoquinone, RH1 (2,5-diaziridinyl-3-(hydroxymethyl)-6-methyl-1,4-benzoquinone), in mice. Biochem Pharmacol. 2000;59:831-7 pubmed
    ..8 microM). The two DTD substrates RH1 and EO9 are clearly metabolised differently, suggesting that RH1 may have different pharmacological properties to those of EO9 in the clinic. ..
  41. Ryan K, Drennan C. Divergent pathways in the biosynthesis of bisindole natural products. Chem Biol. 2009;16:351-64 pubmed publisher
  42. Bentley T. Nucleophilicity parameters for amines, amino acids and peptides in water. Variations in selectivities for quinone methides. Org Biomol Chem. 2011;9:6685-90 pubmed publisher
    ..As the reactivities of QMs decrease, s(E) increases and the response of s(E) to changes in reactivity is larger for QMs than for cations. ..
  43. Di J, Bi S. Aluminum ions accelerated the oxidative stress of copper-mediated melanin formation. Spectrochim Acta A Mol Biomol Spectrosc. 2003;59:3075-83 pubmed
    ..5). ..
  44. Veldhuyzen W, Pande P, Rokita S. A transient product of DNA alkylation can be stabilized by binding localization. J Am Chem Soc. 2003;125:14005-13 pubmed
    ..Pande, P.; Johnson, A. E.; Rokita, S. E. Bioorg. Med. Chem. 2001, 9, 2347-2354]. ..
  45. Veljkovic J, Uzelac L, Molcanov K, Mlinarić Majerski K, Kralj M, Wan P, et al. Sterically congested adamantylnaphthalene quinone methides. J Org Chem. 2012;77:4596-610 pubmed publisher
    ..Exposure of MCF-7 cells treated with 5 to 300 nm irradiation leads to an enhanced antiproliferative effect, in accordance with the activity being due to the formation of QM5. ..
  46. Sugumaran M, Bolton J. Laccase--and not tyrosinase--is the enzyme responsible for quinone methide production from 2,6-dimethoxy-4-allyl phenol. Arch Biochem Biophys. 1998;353:207-12 pubmed
  47. Hothi P, Lee M, Cullis P, Leys D, Scrutton N. Catalysis by the isolated tryptophan tryptophylquinone-containing subunit of aromatic amine dehydrogenase is distinct from native enzyme and synthetic model compounds and allows further probing of TTQ mechanism. Biochemistry. 2008;47:183-94 pubmed
    ..This is attributed to the absence of structural rearrangement prior to H-transfer that limits the rate of TTQ reduction by para-substituted benzylamines in native enzyme. ..
  48. Kulikov A, Arumugam S, Popik V. Photolabile protection of alcohols, phenols, and carboxylic acids with 3-hydroxy-2-naphthalenemethanol. J Org Chem. 2008;73:7611-5 pubmed publisher
    ..The o-quinone methide intermediate can be also trapped by other nucleophiles or converted into a photostable Diels-Alder adduct with ethyl vinyl ether. ..
  49. Jain A, Phillips R, Scally A, Lenaz G, Beer M, Puri R. Response of multiple recurrent TaT1 bladder cancer to intravesical apaziquone (EO9): comparative analysis of tumor recurrence rates. Urology. 2009;73:1083-6 pubmed publisher
    ..Larger prospective randomised trials are warranted to confirm these results. ..
  50. Huang B, Desai A, Tang S, Thomas T, Baker J. The synthesis of a c(RGDyK) targeted SN38 prodrug with an indolequinone structure for bioreductive drug release. Org Lett. 2010;12:1384-7 pubmed publisher
    ..Preliminary studies showed that SN38 is released in the presence of a bioreductive enzyme (DT-diaphorase). ..
  51. Sellars J, Landrum M, Congreve A, Dixon D, Mosely J, Beeby A, et al. Fluorescence quenched quinone methide based activity probes--a cautionary tale. Org Biomol Chem. 2010;8:1610-8 pubmed publisher
    ..However, the relatively slow fragmentation of the carbamate linkage in such a strategy may cause problems of loss of signal or a decoupling of enzyme activity and labelling. ..
  52. Gengan R, Pandian P, Kumarsamy C, Mohan P. Convenient and efficient microwave-assisted synthesis of a methyl derivative of the fused indoloquinoline alkaloid cryptosanguinolentine. Molecules. 2010;15:3171-8 pubmed publisher
  53. Pezzella A, Crescenzi O, Panzella L, Napolitano A, Land E, Barone V, et al. Free radical coupling of o-semiquinones uncovered. J Am Chem Soc. 2013;135:12142-9 pubmed publisher
  54. Shin S, Davidson V. MauG, a diheme enzyme that catalyzes tryptophan tryptophylquinone biosynthesis by remote catalysis. Arch Biochem Biophys. 2014;544:112-8 pubmed publisher
    ..In this process, long range electron transfer is coupled to the radical mediated chemical reactions that are required for TTQ biosynthesis. ..
  55. Albada H, de Vries J, Liu Q, Golub E, Klement N, Herrmann A, et al. Supramolecular micelle-based nucleoapzymes for the catalytic oxidation of dopamine to aminochrome. Chem Commun (Camb). 2016;52:5561-4 pubmed publisher
    ..The catalytic functions of the micellar nucleoapzymes are attributed to the concentration of the substrate, using the aptamer units, in close proximity to the active sites. ..
  56. Bailey S, Wyatt M, Friedlos F, Hartley J, Knox R, Lewis A, et al. Involvement of DT-diaphorase (EC 1.6.99.2) in the DNA cross-linking and sequence selectivity of the bioreductive anti-tumour agent EO9. Br J Cancer. 1997;76:1596-603 pubmed
    ..In contrast, using a Taq polymerase stop assay, monofunctional alkylation was detected in plasmid DNA without metabolic activation, although the sequence selectivity was altered after reduction catalysed by DT-diaphorase. ..
  57. Choudry G, Stewart P, Double J, Krul M, Naylor B, Flannigan G, et al. A novel strategy for NQO1 (NAD(P)H:quinone oxidoreductase, EC 1.6.99.2) mediated therapy of bladder cancer based on the pharmacological properties of EO9. Br J Cancer. 2001;85:1137-46 pubmed
    ..Administration of EO9 in an acidic vehicle could be employed to reduce possible systemic toxicity as any drug absorbed into the blood stream would become relatively inactive due to an increase in pH. ..
  58. Limburg J, Mure M, Klinman J. Cloning and characterization of histamine dehydrogenase from Nocardioides simplex. Arch Biochem Biophys. 2005;436:8-22 pubmed
    ..0+/-1.8 at pH 8.5. k(cat) is also pH dependent and has a reduced substrate deuterium isotope of (D)(k(cat))=1.3+/-0.2...
  59. Zafar K, Siegel D, Ross D. A potential role for cyclized quinones derived from dopamine, DOPA, and 3,4-dihydroxyphenylacetic acid in proteasomal inhibition. Mol Pharmacol. 2006;70:1079-86 pubmed
    ..The ability of endogenous intermediates formed during dopaminergic metabolism to cause proteasomal inhibition provides a potential basis for the selectivity of dopaminergic neuron damage in Parkinson's disease. ..
  60. Meng S, Kaxiras E. Theoretical models of eumelanin protomolecules and their optical properties. Biophys J. 2008;94:2095-105 pubmed
    ..These optical spectra may serve as signatures for identifying intermediate structures. ..
  61. Ximenes V, Maghzal G, Turner R, Kato Y, Winterbourn C, Kettle A. Serotonin as a physiological substrate for myeloperoxidase and its superoxide-dependent oxidation to cytotoxic tryptamine-4,5-dione. Biochem J. 2009;425:285-93 pubmed publisher
    ..Consequently, oxidation of serotonin by myeloperoxidase may profoundly influence inflammatory processes. ..
  62. Arentsen H, Hendricksen K, Hulsbergen van de Kaa C, Reddy G, Oosterwijk E, Alfred Witjes J. The orthotopic Fischer/AY-27 rat bladder urothelial cell carcinoma model to test the efficacy of different apaziquone formulations. Urol Oncol. 2012;30:64-8 pubmed publisher
    ..Apaziquone showed an excellent antitumor activity. The effectiveness of apaziquone in this orthotopic rat bladder tumor model corroborates the clinical observations and implies the validity of this model. ..
  63. Inman M, Moody C. Synthesis of indolequinones from bromoquinones and enamines mediated by Cu(OAc)2.H2O. J Org Chem. 2010;75:6023-6 pubmed publisher
    A Cu(II)-mediated synthesis of indolequinones from the corresponding bromoquinones and enamines is reported...
  64. Lozano J, Munoz P, Nore B, Ledoux S, Segura Aguilar J. Stable expression of short interfering RNA for DT-diaphorase induces neurotoxicity. Chem Res Toxicol. 2010;23:1492-6 pubmed publisher
  65. Arumugam S, Popik V. Dual reactivity of hydroxy- and methoxy- substituted o-quinone methides in aqueous solutions: hydration versus tautomerization. J Org Chem. 2010;75:7338-46 pubmed publisher
    ..Short-lived (?(25°)(C) ? 20 ?s) precursors of o-quinone methides 1 and 2 were detected in the laser flash photolysis of 3a,b and 4a,b. On the basis of their reactivity, benzoxete structures have been assigned to these intermediates. ..
  66. Rossiter C, Modica E, Kumar D, Rokita S. Few constraints limit the design of quinone methide-oligonucleotide self-adducts for directing DNA alkylation. Chem Commun (Camb). 2011;47:1476-8 pubmed publisher
    ..The general lack of sequence restrictions should now allow for alkylation of most any target of interest although reaction is most efficient when the self-adducts contain guanine residues and do not form hairpin structures. ..
  67. McCrane M, Weinert E, Lin Y, Mazzola E, Lam Y, Scholl P, et al. Trapping a labile adduct formed between an ortho-quinone methide and 2'-deoxycytidine. Org Lett. 2011;13:1186-9 pubmed publisher
    ..However, BTI induces a surprising rearrangement driven by overoxidation of a derivative lacking an alkyl substituent at the 4-position of the QM. ..
  68. Tarboush N, Jensen L, Yukl E, Geng J, Liu A, Wilmot C, et al. Mutagenesis of tryptophan199 suggests that hopping is required for MauG-dependent tryptophan tryptophylquinone biosynthesis. Proc Natl Acad Sci U S A. 2011;108:16956-61 pubmed publisher
  69. Sharma A, Li Y, Novalen M, Hayes M, Uetrecht J. Bioactivation of nevirapine to a reactive quinone methide: implications for liver injury. Chem Res Toxicol. 2012;25:1708-19 pubmed publisher
    ..This is the first study to report hepatic covalent binding of NVP and also liver injury in mice. It is likely that the quinone methide metabolite is responsible for NVP-induced liver injury. ..
  70. Sharma K, Iyer A, Sengupta K, Chakrapani H. INDQ/NO, a bioreductively activated nitric oxide prodrug. Org Lett. 2013;15:2636-9 pubmed publisher
    ..Cell-based assays revealed that INDQ/NO induces DNA damage and is a potent inhibitor of cancer cell proliferation. ..
  71. Chiang Y, Kresge A, Zhu Y. Flash photolytic generation and study of p-quinone methide in aqueous solution. An estimate of rate and equilibrium constants for heterolysis of the carbon-bromine bond in p-hydroxybenzyl bromide. J Am Chem Soc. 2002;124:6349-56 pubmed
    ..Comparisons are made of the reactivity of p-quinone methide with p-quinone alpha,alpha-bis(trifluoromethyl)methide as well as p-quinone methide with o-quinone methide. ..
  72. De Iuliis A, Burlina A, Boschetto R, Zambenedetti P, Arslan P, Galzigna L. Increased dopamine peroxidation in postmortem Parkinsonian brain. Biochim Biophys Acta. 2002;1573:63-7 pubmed
    ..The increased peroxidizing activity in Parkinson's patients generates the toxic compound dopaminochrome which may play a role in the pathogenesis of this disease. ..
  73. Freccero M, Gandolfi R, Sarzi Amadè M. Selectivity of purine alkylation by a quinone methide. Kinetic or thermodynamic control?. J Org Chem. 2003;68:6411-23 pubmed
    ..The ability of o-QM to form several metastable adducts with purine nucleobases (at guanine N7 and O(2), and adenine N1) in water suggests that the above adducts may act as o-QM carriers. ..
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    ..This high-order dependency is attributed to a proton-relay transfer involving 3 equiv of ROH in each case. ..
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    ..Cycloadditions of various enol ethers and o-QMs are examined, and diastereoselectivities >95% are obtained with trans-2-phenyl-1-cyclohexanol and 2,2-diphenylcyclopentanol vinyl ethers. ..
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    ..The reversibility of QM reaction can now be predictably adjusted for any desired application. ..
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    ..The reactivity of the arylboronic acids/esters and the inhibition or facilitation of QM formation can now be predictably adjusted. This adjustment is important as some applications may benefit and others may be limited by QM generation. ..
  89. Paz T, Dos Santos V, Inácio M, Pina E, Pereira A, Furlan M. Production of the quinone-methide triterpene maytenin by in vitro adventitious roots of Peritassa campestris (Cambess.) A.C.Sm. (Celastraceae) and rapid detection and identification by APCI-IT-MS/MS. Biomed Res Int. 2013;2013:485837 pubmed publisher
    ..The highest level of maytenin--972.11? ? g·g?¹ dry weight--was detected at seven days of cultivation; this value was 5.55-fold higher than that found in the roots of seedlings grown in a greenhouse. ..
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    ..The N parameters [5.51 for P(OPh)3, 10.36 for P(OBu)3, 14.33 for PPh3, 15.49 for PBu3, 18.39 for P(4-Me2NC6H4)3] are compared with the reactivities of other classes of nucleophiles (see, www.cup. uni-muenchen.de/oc/mayr). ..