scholarly journals Identification of Human Liver Cytochrome P450s Involved in the Microsomal Metabolism of the Antihistaminic Drug Loratadine

1995 ◽  
Vol 107 (1-3) ◽  
pp. 420-420 ◽  
Author(s):  
Nathan Yumibe ◽  
Keith Huie ◽  
Kwang-Jong Chen ◽  
Robert P. Clement ◽  
Mitchell N. Cayen
2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Lendelle Raymond ◽  
Nikita Rayani ◽  
Grace Polson ◽  
Kylie Sikorski ◽  
Ailin Lian ◽  
...  

Vorozole and letrozole are third-generation aromatase (cytochrome P450 19A1) inhibitors. [11C]-Vorozole can be used as a radiotracer for aromatase in living animals but when administered by IV, it collects in the liver. Pretreatment with letrozole does not affect the binding of vorozole in the liver. In search of finding the protein responsible for the accumulation of vorozole in the liver, fluorometric high-throughput screening assays were used to test the inhibitory capability of vorozole and letrozole on a series of liver cytochrome P450s (CYP1A1, CYP1A2, CYP2A6, and CYP3A4). It was determined that vorozole is a potent inhibitor of CYP1A1 (IC50 = 0.469 μM) and a moderate inhibitor of CYP2A6 and CYP3A4 (IC50 = 24.4 and 98.1 μM, resp.). Letrozole is only a moderate inhibitor of CYP1A1 and CYP2A6 (IC50 = 69.8 and 106 μM) and a very weak inhibitor of CYP3A4 (<10% inhibition at 1 mM). Since CYP3A4 makes up the majority of the CYP content found in the human liver, and vorozole inhibits it moderately well but letrozole does not, CYP3A4 is a good candidate for the protein that [11C]-vorozole is binding to in the liver.


2020 ◽  
Author(s):  
Sergey Bukhdruker ◽  
Tatsiana Varaksa ◽  
Irina Grabovec ◽  
Egor Marin ◽  
Polina Shabunya ◽  
...  

AbstractSpreading of the multidrug-resistant (MDR) strains of the deadliest pathogen Mycobacterium tuberculosis (Mtb) generates the need for new effective drugs. SQ109 showed activity against resistant Mtb and already advanced to Phase II/III clinical trials. Fast SQ109 degradation is attributed to the human liver Cytochrome P450s (CYPs). However, no information is available about interactions of the drug with Mtb CYPs. Here, we show that Mtb CYP124, previously assigned as a methyl-branched lipid monooxygenase, binds and hydroxylates SQ109 in vitro. A 1.25 Å-resolution crystal structure of the CYP124–SQ109 complex unambiguously shows two conformations of the drug, both positioned for hydroxylation of the ω-methyl group in the trans position. The hydroxylated SQ109 presumably forms stabilizing H-bonds with its target, the Mycobacterial membrane protein Large 3 (MmpL3). We anticipate that Mtb CYPs could function as analogs of drug-metabolizing human CYPs affecting pharmacokinetics and pharmacodynamics of antitubercular (anti-TB) drugs.


2007 ◽  
Vol 35 (12) ◽  
pp. 2186-2195 ◽  
Author(s):  
Anima Ghosal ◽  
Ragu Ramanathan ◽  
Yuan Yuan ◽  
Neil Hapangama ◽  
Swapan K. Chowdhury ◽  
...  

2009 ◽  
Vol 72 (10) ◽  
pp. 1748-1754 ◽  
Author(s):  
Yun Fan ◽  
Emanuel M. Schreiber ◽  
Billy W. Day

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