Mechanism of action of the following drug is FALSE
Correct Answer: Fluconozole -- Mitosis inhibition
Description: (C) Fluconozole - Mitosis inhibition > Antifungal activity of Amphotericin B depends principally on its binding to a sterol moiety, primarily ergosterol that is present in the membrane of sensitive fungi. By virtue of their interaction with these sterols, polyenes appear to form pores or channels that increase the permeability of the membrane, allowing leakage of a variety of small molecules. At concentrations achieved following systemic administration, the major effect of imidazoles and triazoles on fungi is inhibition of 14-a-sterol demethylase, a microsomal cytochrome P450 (CYP) enzyme. Imidazoles and triazoles thus impair the biosynthesis of ergosterol for the cytoplasmic membrane and lead to the accumulation of 14-a-methylsterols. These rnethylsterols may disrupt the close packing of acyl chains of phospholipids, impairing the functions of certain membrane-bound enzyme systems such as ATPase and enzymes of the electron transport system and thus inhibiting growth of the fungi. All susceptible fungi are capable of deaminating flucytosine to 5-fluorouracil, a potent antimetabolite that is used in cancer chemotherapy. Fluorouracil is metabolized first to 5-fluorouracil-ribose monophosphate (5-FUMP) by the enzyme uracil phosphoribosyl transferase (UPRTase, also called uridine monophosphate pyrophosphorylase). As in mammalian cells, 5-FUMP then is either incorporated into RNA (via synthesis of 5-fluorouridine triphosphate) or metabolized to 5-fluoro2'- deoxyuridine-5'-monophosphate (5-FdUMP), a potent inhibitor of thymidylate synthetase.DNA synthesis is impaired as the ultimate result of this latter reaction. The selective action of flucytosine is due to the lack or low levels of cytosine deaminase in mammalian cells, which prevents metabolism to fluorouracil.Lanosterolfluconazole-demythylaze ergosterol
Category:
Pharmacology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now