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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.
Storage and Rehydration: Store freeze-dried solid at 2-8°C. Rehydrate with the indicated volume of dH2O and centrifuge if not clear. Prepare working dilution on day of use. Product is stable for about 6 weeks at 2-8°C as an undiluted liquid.
Extended Storage after Rehydration: Aliquot and freeze at -70°C or below. Avoid repeated freezing and thawing. Alternatively, add an equal volume of glycerol (ACS grade or better) for a final concentration of 50%, and store at -20°C as a liquid.
Expiration date: one year from date of rehydration. The expiration date may be extended if test results are acceptable for the intended use.
1:100 - 1:400 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.
Cy5 conjugates are excited maximally at 650 nm and fluoresce maximally at 670 nm. They can be excited to about 98% of maximum with a krypton/argon laser (647 nm line) or to about 63% of maximum with a helium/neon laser (633 nm line). Cy5 can be used with a variety of other fluorophores for multiple labeling due to a wide separation of its emission from that of shorter wavelength-emitting fluorophores. However, we recommend Alexa Fluor® 647 as the preferred far-red-fluorescing dye because it is brighter than Cy5 in aqueous mounting media. The reverse is true when mounting in non-polar, plastic mounting media, i.e. Cy5 is brighter than other far-red-fluorescing dyes, including Alexa Fluor® 647 and DyLight 650.
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.
Cy is a trademark of GE Healthcare Bio-Sciences Ltd. Jackson ImmunoResearch is licensed by GE Healthcare Bio-Sciences Ltd. to manufacture and sell conjugates of Cy2, Cy3, and Cy5 reactive dyes under US Patent Number 5,268,486, and other patents pending.