Products

Liver Metabolism & Clearance Assays

The liver is the main site of metabolism clearance and most drugs are cleared by CYP proteins which are responsible for Phase I biotransformation reactions, in which lipophilic drugs and other xenobiotic compounds are transformed to more hydrophilic products to facilitate excretion from the body. Drugs can decrease but also increase the activity of one or more CYP enzymes, which alters the rate at which the drug is degraded and cleared from the body. That can render the drug ineffective or may not prevent the drug from accumulating to toxic levels. The most common mechanism underlying drug-drug interactions is the inhibition of cytochrome P450 activities. Thus, new drugs candidates have to be tested against cytochrome P450 enzymes in several ways. Among the different CYP proteins, CYP1, CYP2, CYP3 and CYP4 are the most important in terms of drug biotranformations, especially CYP3A4, which is the most prevalent CYP in the body and metabolises several drugs.
Aromatase (CYP19A) is a member of the cytochrome P450 monooxidase (CYP) family of microsomal xenobiotic metabolism enzymes which plays a critical role in steroidogenesis, catalyzing the conversion of androgenic hormones into estrogens. Aromatase inhibitors have become useful in the treatment of patients with estrogen-dependent breast cancer.
Aromatases are mostly found in the ovary and placenta, which are the major sources of estrogen production, but also in other tissues, such as liver, kidney, adrenals, brain, muscle and subcutaneous fat where it is also active in producing estrogens,

PromoKine’s Cytochrome P450 (CYP) Activity Assay Kits enable rapid measurement of native or recombinant CYP activity in biological samples such as liver microsomes. The assays utilize a non-fluorescent CYP substrate that is converted into a highly fluorescent metabolite detected in the visible range, ensuring a high signal-to-background ratio with little interference by autofluorescence.

PromoKine’s Cytochrome P450 (CYP) Screening Kits enable rapid screening of drugs and other new chemical entities (NCEs) for compound-CYP interaction in a reliable, high-throughput assay. The kits provide a yeast microsomal preparation of human CYP and cytochrome P450 reductase (CPR) enzymes and the assays utilize a non-fluorescent CYP substrate that is converted into a highly fluorescent metabolite, ensuring a high signal-to-background ratio with little interference by autofluorescence.

Our Cytochrome P450 Reductase (CPR) Activity Assay Kit accurately and sensitively measures CPR activity by coupling oxidation of NADPH by CPR with reduction of a nearly colorless probe into a brightly colored product, with the rate of color generation being directly proportional to the CPR activity.


Uridine diphospho-glucuronosyltransferases (UGTs) are responsible for the vast majority of Phase II biotransformation (conjugation) reactions, in which a hydrophilic moiety is attached to small molecule drugs and other xenobiotics to facilitate their rapid excretion from the body.
PromoKine’s UGT Activity Assay/Ligand Screening Kit enables rapid fluorometric measurement of native or recombinant UGT activity in biological samples such as liver microsomes and can also be used to assess the effect of drugs and other novel compounds on UGT activity.


Monoamine Oxidases (MAOs) which catalyze the oxidative deamination of a large number of biogenic and xenobiotic monoamines are, besides the CYP450 enzymes,  the most important Phase I biotransformation enzymes. Thus, MAO assays are a common tool in drug development. MAOs are also the target of a number of inhibitor drug candidates.  
PromoKine's Monoamine Oxidase Activity Assay Kit provides a sensitive assay to detect total monoamine oxidase activity as well as MAO-A and MAO-B isoenzyme activities separately in the presence of the specific inhibitors for MAO-A and MAO-B, clorgyline and selegiline. The assay is based on the fluorometric detection of H2O2, one of the byproducts generated during the oxidative deamination of the MAO Substrate and can detect as little as 5 µU of MAO enzymatic activity.


Microsomes are spherical vesicle-like structures formed from membrane fragments following homogenization and fractionation of eukaryotic cells. Microsomal preparations are an affordable and convenient in vitro system for assessing Phase I biotransformation reactions, as they contain all of the xenobiotic-metabolizing CYP isozymes and the membrane-bound flavoenzymes required for function of the multicomponent P450 enzyme system. Thus, microsomes isolated from liver tissue are used extensively in pharmaceutical research and environmental science to study the metabolism of drugs, organic pollutants and other xenobiotic compounds by the cytochrome P450 (CYP) enzyme superfamily.
PromoKine’s Microsome Isolation Kit enables preparation of active microsomes in about one hour, without the need for ultracentrifugation or sucrose gradient fractionation. The kit contains sufficient reagents for simple and convenient procedures, yielding microsomes from roughly 25 grams of tissue or cultured cells.

 

 

References, Questions & Answers

Product Name Description Size Catalog Number Information Prices
Cytochrome P450 Reductase (CPR) Activity Assay Kit Rapid, convenient and sensitive colorimetric CPR assay kit for 96-well plates. 100 assays PK-CA577-K700 click to select country
Cytochrome P450 3A4 (CYP3A4) Activity Assay Kit Rapid fluorometric assessment of native/recombinant CYP3A4 activity in lysates or microsomal fractions prepared from tissues or cells. 200 assays PK-CA577-K701 click to select country
Cytochrome P450 3A4 (CYP3A4) Inhibitor Screening Kit Fluorometric assay for high-throughput compatible, quick and easy screening for CYP3A inhibitors or ligands. 200 assays PK-CA577-K702 click to select country
Cytochrome P450 2D6 (CYP2D6) Activity Assay Kit Rapid fluorometric assessment of native/recombinant CYP2D6 activity in lysates or microsomal fractions prepared from tissues or cells. 200 assays PK-CA577-K703 click to select country
Cytochrome P450 2D6 (CYP2D6) Inhibitor Screening Kit Fluorometric assay for high-throughput compatible, quick and easy screening for CYP2D6 inhibitors or ligands. 200 assays PK-CA577-K704 click to select country
Cytochrome P450 2C19 (CYP2C19) Activity Assay Kit Rapid fluorometric assessment of native/recombinant CYP2C19 activity in lysates or microsomal fractions prepared from tissues and cells. 100 assays PK-CA577-K848 click to select country
Cytochrome P450 2C19 (CYP2C19) Inhibitor Screening Kit Fluorometric assay for high-throughput compatible, quick and easy screening for CYP2C19 inhibitors or ligands. 100 assays PK-CA577-K849 click to select country
Cytochrome P450 1A2 (CYP1A2) Activity Assay Kit Rapid fluorometric assessment of native/recombinant CYP1A2 activity in lysates or microsomal fractions prepared from tissues and cells. 100 assays PK-CA577-K893 click to select country
Cytochrome P450 1A2 (CYP1A2) Inhibitor Screening Kit Fluorometric assay for high-throughput compatible, quick and easy screening for CYP1A2 inhibitors or ligands. 100 assays PK-CA577-K894 click to select country
Cytochrome P450 2C9 (CYP2C9) Activity Assay Kit Rapid fluorometric assessment of native/recombinant CYP2C9 activity in lysates or microsomal fractions prepared from tissues and cells. 100 assays PK-CA577-K895 click to select country
Cytochrome P450 2C9 (CYP2C9) Inhibitor Screening Kit Fluorometric assay for high-throughput compatible, quick and easy screening for CYP2C9 inhibitors or ligands. 100 assays PK-CA577-K896 click to select country
Aromatase (CYP19A) Activity Assay Kit Rapid fluorescent measurement of native/recombinant Aromatase activity in lysates or microsomal fractions prepared from tissues and cells. 100 assays PK-CA577-K983 click to select country
Aromatase (CYP19A) Inhibitor Screening Kit High-throughput compatible, quick and easy screening for Aromatase inhibitors or ligands. 100 assays PK-CA577-K984 click to select country
Monoamine Oxidase Activity Assay Kit Fluorometric measurement of total MAO, MAO-A and MAO-B activities in various biological samples 100 assays PK-CA577-K795 click to select country
Monoamine Oxidase A (MAO-A) Inhibitor Screening Kit High-throughput fluorometric assay to screen/study/characterize potential inhibitors of monoamine oxidase A 100 assays PK-CA577-K796 click to select country
Monoamine Oxidase B (MAO-B) Inhibitor Screening Kit High-throughput fluorometric assay to screen/study/characterize potential inhibitors of monoamine oxidase B 100 assays PK-CA577-K797 click to select country
UGT Activity Assay / Ligand Screening Kit Simple and sensitive fluorometric assay for UGT Activity in biological samples. 100 assays PK-CA577-K692 click to select country
Microsome Isolation Kit Simple and convenient method to isolate active microsomes 50 isolations PK-CA577-K249 click to select country