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.
1:100 - 1:800 for most applications
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.
DyLight 405-conjugated secondary antibodies are excited maximally at about 400 nm and fluoresce with a peak at about 421 nm. They are very bright and photostable, but their optimal use is limited to microscopes or flow cytometers equipped with a 405 nm laser and a 420 nm emission filter. Under these conditions, it is possible to perform effective 4-color imaging with good color separation, good photostability, and high sensitivity. The combination of DyLight 405, Alexa Fluor® 488, Rhodamine Red-X, and Alexa Fluor® 647 provides for maximum color separation. Another 4-color dye combination, which may be equally effective but has slightly less color separation, is DyLight 405, Alexa Fluor® 488, Cy3, and Alexa Fluor® 647. DyLight 405 conjugates are an excellent choice for blue-fluorescing secondary antibodies in multi-color labeling protocols.
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.
DyLight™ is a trademark of Thermo Fisher Scientific, Inc. and its subsidiaries.