Cytochrome P-450 Enzyme System (Cytochrome P450)

A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.

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Networked: 3623 relevant articles (84 outcomes, 414 trials/studies)

Relationship Network

Bio-Agent Context: Research Results

Experts

1.	Zeldin, Darryl C: 28 articles (07/2015 - 03/2003)
2.	Falck, John R: 26 articles (03/2015 - 07/2004)
3.	El-Kadi, Ayman O S: 20 articles (08/2015 - 04/2004)
4.	Malik, Kafait U: 16 articles (01/2016 - 02/2002)
5.	Gonzalez, Frank J: 14 articles (01/2016 - 09/2002)
6.	Ingelman-Sundberg, Magnus: 14 articles (01/2015 - 09/2003)
7.	Morgan, Edward T: 14 articles (01/2014 - 12/2002)
8.	Lee, Craig R: 13 articles (10/2014 - 10/2007)
9.	Wang, Lihua: 12 articles (07/2015 - 08/2007)
10.	Edin, Matthew L: 12 articles (10/2014 - 07/2007)

Related Diseases

1.	Neoplasms (Cancer) 03/01/2010 - "One of the major outcomes of recent studies include significantly improved effectiveness of cytochrome P450 directed enzyme pro-drug delivery tools when used in conjunction with P35, which may help in alleviating drug resistance in tumor cells and simultaneously prolonging the cytotoxic effects of anti-cancer drugs. " 10/08/2005 - "A significant reduction in total cytochrome P-450 activity was observed in tumor and tumor-adjacent tissues versus normal stomach. " 01/01/2015 - "Also, various studies have found the expression and activity of orphan human cytochrome P450 4X1 in cancer. " 07/15/2013 - "In the current study, we examined the influence of these compounds on cytochrome P450 3A4 (CYP3A4) and 2C9 (CYP2C9) enzymatic activity and gene expression in HepG2 tumor cells. " 07/01/2013 - "The purpose of this study was (1) to compare the number and types of prescription medications and over-the-counter medications between BCS and midlife women without cancer and (2) to assess possible drug-drug interactions by evaluating the cytochrome P450 isoform properties of medications (inductors and inhibitors) in both groups. "
2.	Body Weight (Weight, Body) 09/01/1981 - "In male rats, cytochrome P-450 content based on 100 g body weight decreased only in old rats as compared with immature rats, whereas a significant reduction was observed in female rats in the content based on mg microsomal protein as well as based on 100 g body weight in young and old animals. " 01/01/2014 - "Analyses were performed using NONMEM, and the impacts of body weight, age, race, sex, formulation, liver function, and cytochrome P450 2B6 (CYP2B6)-G516T and multidrug-resistance transporter gene (MDR1)-C3435T polymorphisms were assessed. " 10/01/2013 - "Physiological data related to changes in maternal body weight, tissue volume, cardiac output, renal function, blood flows, and cytochrome P450 activity were collected from the literature and incorporated into the structural PBPK model that describes HV or PP women PK data. " 07/01/2008 - "Both groups did not differ from each other significantly in body weight gain, hepatosomatic index, and condition factor Hepatic level of cytochrome P450 was lower in PSP group than control group. " 01/01/2004 - "Sex-based differences in the four major factors that contribute to interindividual pharmacokinetic variability--bioavailability, distribution, metabolism, and elimination--are theorized to stem from variations between men and women in factors such as body weight, plasma volume, gastric emptying time, plasma protein levels, cytochrome P450 activity, drug transporter function, and excretion activity. "
3.	Inflammation 01/01/2015 - "Acute and chronic toxicity, cytochrome p450 enzyme inhibition, and HERG channel blockade studies with a polyherbal, ayurvedic formulation for inflammation." 09/18/1999 - "These studies indicate that inflammation localized to the CNS causes an alteration in the levels and activity of a major cytochrome P450 form in the brain. " 06/01/2015 - "Inflammation-associated microRNA-130b down-regulates cytochrome P450 activities and directly targets CYP2C9." 01/01/2015 - "However, it is difficult to predict changes in drug exposure in patients because the response to inflammation varies depending on the disease state, its time course, and the cytochrome P450 involved. " 11/01/2014 - "Human cytochrome P450 epoxygenases: variability in expression and role in inflammation-related disorders."
4.	Hemorrhage 07/01/2012 - "Systematic review and meta-analysis of the association between cytochrome P450 2C19 genotype and bleeding." 01/01/2009 - "Adjusted odds ratio (OR) for bleeding was highest for cytochrome P450 2C9 (CYP2C9) inhibitors (OR 3.6; 95% confidence interval (CI) 2.4-5.6). " 12/01/2007 - "Cytochrome P450 CYP2C9 polymorphism and NSAID-related acute gastrointestinal bleeding." 09/01/2007 - "Patients with either Cytochrome P-450 CYP2C9*2, CYP2C9*3, or VKORC1*2 genotype (c.-1639G>A) require significantly reduced doses, and are at a higher risk of serious bleeding. " 08/01/2013 - "(13)C-methacetin breath test ((13)C-MBT) - a sensitive non-invasive probe of cytochrome P-450 1A2 activity - was performed in 15 women on day 14, 15, 16, 17 or 18 of intake of their COC (containing EE), and between day 1 and 5 during the withdrawal bleeding, as well as in nine women not using hormonal contraception during the luteal phase of their cycle (between the 17th and the 23rd day), and between day 1 and 5 during menstruation. "
5.	Fibrosis (Cirrhosis) 05/01/1995 - "Pharmacokinetic studies in patients with cirrhosis have shown a decreased clearance of drugs metabolized by cytochrome P450, whereas drugs metabolized by glucuronidation frequently have a normal elimination. " 01/01/2000 - "In the presence of cirrhosis, portosystemic shunting occurs and cytochrome P450 activity is reduced. " 07/01/1987 - "The available evidence supports the assertion that specific forms of cytochrome P450 are subject to altered regulation in cirrhosis." 12/01/1969 - "The effect of cirrhosis of the liver on microsomal detoxications and cytochrome P-450." 01/01/2013 - "Although the induction of cytochrome P450 (CYP) has long been investigated in patients with cirrhosis, the question whether liver dysfunction impairs the response to CYP inducers still remains unresolved. "

Related Drugs and Biologics

1.	Enzymes
2.	Isoenzymes
3.	Cytochrome P-450 CYP1A2 (CYP1A2)
4.	Omeprazole (Esomeprazole)
5.	Aromatase (CYP19)
6.	Antipyrine (Phenazone)
7.	Cytochromes b5 (Cytochrome b5)
8.	Glutathione Transferase (Glutathione S-Transferase)
9.	Protein Isoforms (Isoforms)
10.	Acids

Related Therapies and Procedures

1.	Drug Therapy (Chemotherapy)
2.	Castration
3.	Total Parenteral Nutrition
4.	Transplants (Transplant)
5.	Resuscitation