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CGP1 Sigma

Glutathione Peroxidase Cellular Activity Assay Kit

Synonym: Cellular glutathione peroxidase, c-GPx



Related Categories Cell Analysis, Cell Biology, Cell Signaling and Neuroscience, Cell Stress, Nitric Oxide and Cell Stress,
usage   sufficient for 100 tests
shelf life   Kit is stable for 24 months when unopened.
shipped in   wet ice
storage temp.   −20°C


Frequently Asked Questions

Frequently Asked Questions are available for this Product.

Other Notes

This kit was tested with rabbit reticulocyte lysate and with glutathione peroxidase enzyme.

General description

The Glutathione Peroxidase Cellular Activity Assay kit is used to measure glutathione peroxidase in tissue extracts. The assay is based on the oxidation of glutathione (GSH) to oxidized glutathione (GSSG). This is catalyzed by GPx coupled to the recycling of GSSG back to GSH utilizing glutathione reductase and NADPH. The decrease in NADPH absorbance measured at 340 nm during the oxidation of NADPH to NADP is indicative of glutathione peroxidase activity since the enzyme is the rate-limiting factor of the coupled reactions.

Price and Availability

All labs need water

Kit component only


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Glutathione Peroxidase Assay Buffer 120 mL SDS    
NADPH Assay Reagent 5 vials SDS    

Standard component


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tert-Butyl hydroperoxide 1 mL SDS    
Safety & Documentation

Safety Information

Signal word 
Precautionary statements 
UN 3316 9
WGK Germany 


Certificate of Analysis

Certificate of Origin

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis. These documents are located on the product detail page under Useful Links & Tools. Click on the following link to search for a Certificate of Analysis. Please click the following link to see the details on our Product Dating Information.
How do I get lot-specific information or a Certificate of Analysis?
A Certificate of Analysis is available by lot number and can be obtained through our Advanced Search Option: http://www.sigmaaldrich.com/catalog/AdvancedSearchPage.do
Can Product CGP1, Glutathione Peroxidase Cellular Activity Assay Kit, be run in a 96 well plate?
Yes, but you would need to have a plate reader that has a kinetic function as this is a kinetic assay.
How should I prepare my sample for analysis with Product CGP1, Glutathione Peroxidase Cellular Activity Assay Kit?
The cells must be lysed before assaying with this kit.  The best way to perform lysis is to incubate the cells with hypotonic buffer (at least 2 volumes and better with 3-4 volumes, depending on the expected level of peroxidase in these cells). Let them swell and homogenize with a Dounce homogenizer. Centrifuge the homogenate at 10,000 × g and use the supernatant for the assay.  If a detergent is used for lysis, only use a peroxide-free detergent and follow the instructions in the Bulletin: "Nonionic detergents such as TWEEN and TRITON X-100 that contain high levels of endogenous peroxides will raise the apparent activity. If these detergents are vital to the extraction of the proteins of interest, a low peroxide detergent should be used such as Product Codes X-100-PC (TRITON X-100), P 6585 (TWEEN 20), or P 8192 (TWEEN 80)."
Can Product CGP1, Glutathione Peroxidase Cellular Activity Assay Kit, be used with tissue samples?
We have not tested the CGP1 assay with tissue samples. However, we suggest that the customer perform a small-scale pilot experiment using our CelLytic-MT lysis buffer (Product No. C3228). The buffer enables efficient extraction of tissue proteins. It does not contain any of the interfering agents that are listed on the kit bulletin.
What type of readings do I get with Product CGP1, Glutathione Peroxidase Cellular Activity Assay Kit?
There is a decrease in absorbance during the assay. The OD values decrease with the increase in reaction time. The slope of the reduction in OD (delta OD per minute) is the value used to determine the enzyme units.
What dilution should I use for my sample when using Product CGP1, Glutathione Peroxidase Cellular Activity Assay Kit?
In general, when human erythrocytes were assayed for the enzyme, the sample was diluted 10-fold (15 mg peroxidase per mL) and a 20 μl sample gave a decrease of 0.032 OD340 per minute. Too much enzyme will underestimate the apparent activity of the sample. When rabbit reticulocytes were assayed at a 10-fold dilution (10 mg peroxidase per mL), 20 μl gave a decrease of 0.065 OD340 per minute.
How do I find price and availability?
There are several ways to find pricing and availability for our products.  Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers. 
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS. To access the shipping information for this material, use the link on the product detail page for the product, or search here. 
My question is not addressed here, how can I contact Technical Service for assistance?
Use the option to the right to "Ask a Question" by email of a Technical Service Scientist.
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Protocols & Articles


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