On the Mechanism of Action of Cytochrome P450: Evaluation of Hydrogen Abstraction in Oxygen-Dependent Alcohol Oxidation

Biochemistry ◽  
1994 ◽  
Vol 33 (21) ◽  
pp. 6442-6449 ◽  
Author(s):  
Alfin D. N. Vaz ◽  
Minor J. Coon
Keyword(s):  
Cytochrome P450 ◽  
Mechanism Of Action ◽  
Hydrogen Abstraction ◽  
Alcohol Oxidation

scholarly journals Studies on the Antileishmanial Mechanism of Action of the Arylimidamide DB766: Azole Interactions and Role of CYP5122A1

2014 ◽  
Vol 58 (8) ◽  
pp. 4682-4689 ◽  
Author(s):  
Trupti Pandharkar ◽  
Xiaohua Zhu ◽  
Radhika Mathur ◽  
Jinmai Jiang ◽  
Thomas D. Schmittgen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Mechanism Of Action ◽  
Leishmania Donovani ◽  
Synergistic Activity ◽  
Wild Type ◽  
Content Type ◽  
Axenic Amastigotes ◽  
Intracellular Parasites

ABSTRACTArylimidamides (AIAs) are inspired by diamidine antimicrobials but show superior activity against intracellular parasites. The AIA DB766 {2,5-bis[2-(2-i-propoxy)-4-(2-pyridylimino)aminophenyl]furan hydrochloride} displays outstanding potency against intracellularLeishmaniaparasites and is effective in murine and hamster models of visceral leishmaniasis when given orally, but its mechanism of action is unknown. In this study, through the use of continuous DB766 pressure, we raisedLeishmania donovaniaxenic amastigotes that displayed 12-fold resistance to this compound. These DB766-resistant (DB766R) parasites were 2-fold more sensitive to miltefosine than wild-type organisms and were hypersensitive to the sterol 14α-demethylase (CYP51) inhibitors ketoconazole and posaconazole (2,000-fold more sensitive and over 12,000-fold more sensitive than the wild type, respectively). Western blot analysis of DB766R parasites indicated that while expression of CYP51 is slightly increased in these organisms, expression of CYP5122A1, a recently identified cytochrome P450 associated with ergosterol metabolism inLeishmania, is dramatically reduced in DB766R parasites.In vitrosusceptibility assays demonstrated that CYP5122A1 half-knockoutL. donovanipromastigotes were significantly less susceptible to DB766 and more susceptible to ketoconazole than their wild-type counterparts, consistent with observations in DB766R parasites. Further, DB766-posaconazole combinations displayed synergistic activity in both axenic and intracellularL. donovaniamastigotes. Taken together, these studies implicate CYP5122A1 in the antileishmanial action of the AIAs and suggest that DB766-azole combinations are potential candidates for the development of synergistic antileishmanial therapy.

Prediction of Activation Energies for Hydrogen Abstraction by Cytochrome P450

2006 ◽  
Vol 49 (22) ◽  
pp. 6489-6499 ◽  
Author(s):  
Lars Olsen ◽  
Patrik Rydberg ◽  
Thomas H. Rod ◽  
Ulf Ryde
Keyword(s):  
Cytochrome P450 ◽  
Hydrogen Abstraction ◽  
Activation Energies
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