F(ab')2 fragment antibodies are generated by pepsin digestion of whole IgG antibodies to remove most of the Fc region while leaving some of the hinge region. F(ab')2 fragments have two antigen-binding Fab portions linked together by disulfide bonds and therefore they are divalent. The average molecular weight is about 110 kDa. They are used for specific applications, such as to avoid binding of secondary antibodies to live cells with Fc receptors or to Protein A or Protein G.
Store freeze-dried powder at 2-8°C. When ready to use, rehydrate with indicated volume of d. water and centrifuge if not clear. Product is stable for about 6 weeks at 2-8°C as an undiluted liquid. Prepare working dilution fresh each day. For extended storage after rehydration, add an equal volume of glycerol (ACS grade or better) for a final concentration of 50%, and store at -20°C as a liquid. Note: after the addition of glycerol, the concentration of protein and buffer salts is one-half of the original. Alternatively, aliquot and freeze the product at -70°C or below in the absence of glycerol. Avoid repeated freezing and thawing.
Expiration date: one year from date of rehydration. However, the expiration date may be extended if the product is stored according to the recommendation and the test results are acceptable for its intended use.
1:500 - 1:5,000 for immunohisto/cytochemistry
1:5,000 - 1:100,000 for ELISA and Western blotting with chromogenic substrates
1:10,000 - 1:200,000 for Western blotting with ECL substrates
Dilution factors are presented in the form of a range because the optimal dilution is a function of many factors, such as antigen density, permeability, etc. The actual dilution used must be determined empirically.
Horseradish peroxidase (HRP) conjugates are prepared by a modified Nakane and Kawaoi procedure (J. Histochem. Cytochem. 1974. 22, 1084). Peroxidase conjugates are commonly used for immunohistochemistry, Western blotting, and ELISA. Affinity-purified anti-horseradish peroxidase and conjugates are available for detection of horseradish peroxidase antigen or for signal amplification of HRP-containing reagents. For immunostaining of mammalian cells, an advantage of using anti-horseradish peroxidase is reduced background, since the antibody does not recognize the endogenous peroxidase-like enzymes found in those cells.
This product is for IN VITRO RESEARCH USE ONLY. It is not a medical device and it is not intended for diagnostic or therapeutic purposes.