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Fab fragment antibodies are generated by papain digestion of whole IgG antibodies to remove the entire Fc portion, including the hinge region. These antibodies are monovalent, containing only a single antigen binding site. The molecular weight of Fab fragments is about 50 kDa.
Storage and Rehydration: Store freeze-dried solid at 2-8°C. Rehydrate with the indicated volume of dH2O (see product specification sheet) and centrifuge if not clear. Store at 2-8°C – do not freeze. Prepare working dilution on day of use.
Expiration date: six months from date of rehydration. The expiration date may be extended if test results are acceptable for the intended use.
1:50 - 1:200 for sequential labeling applications.
To complex with primary antibody in solution, use 1:1 weight ratio of R-PE:primary antibody (approximate 15:1 molar ratio of Fab:primary antibody). Vortex and incubate for 30 minutes at room temperature prior to use. Titrate complex to optimal dilution for assay.
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.
Phycoerythrin (R-PE) is among several kinds of light-harvesting phycobiliproteins found in red, blue-green, and cryptomonad algae. We offer R-PE, the form found in red macrophytic algae (seaweed). After phycobiliproteins are conjugated to secondary antibodies, there is little fluorescence quenching, which results in conjugates of high specific fluorescence compared with conventional fluorophore-antibody conjugates. R-PE can be excited by light over a wide range of the visible spectrum is highly water soluble, has a relatively low isoelectric point, and lacks potentially sticky carbohydrates.
It should be noted that the relatively high molecular weight of R-PE may preclude its use in procedures requiring good penetration into cells and tissues. It is predominantly intended for surface labeling of cells for flow cytometry.
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.
R-Phycoerythrin is licensed under U.S. Patents 4,5220,110 and 4,542,104; E.P.O. Patent 0076695; and Canadian Patent 1179942.