


Target: Human
Host: Goat
Antibody Format: Fab Fragment
Specificity: IgG, Fcγ fragment specific
Conjugate: Alexa Fluor® 647
Product Category: FabuLight™ - Affinity-Purified Fc Specific Fab Fragments
Clonality: Polyclonal
RRID: AB_2632454
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. 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.
Buffer: 0.01M Sodium Phosphate, 0.25M NaCl, pH 7.6
Stabilizer: 15 mg/ml Bovine Serum Albumin (IgG-Free, Protease-Free)
Preservative: 0.05% Sodium Azide
Suggested Working Concentration or Dilution Range:
1:100 - 1:800 for sequential labeling applications.
To complex with primary antibody in solution, use 1:1 weight ratio of Fab:primary antibody (3:1 molar ratio). 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.
Alexa Fluor® 647
Amax: 651 Emax: 667nm Alexa Fluor® 647-conjugated antibodies absorb light maximally around 651 nm and fluoresce maximally around 667 nm. They are brighter than Cy5 and DyLight 650 in aqueous mounting media. Alexa Fluor® 647- and APC-conjugated secondary antibodies are the best choice for flow cytometry when secondary antibodies fluorescing at these wavelengths are desired. Alexa Fluor® 647 conjugates are the best choice of far red-emitting dyes for multiple-labeling detection with a confocal microscope.
A significant advantage of using Alexa Fluor® 647 over lower wavelength-emitting dyes is the low autofluorescence of biological specimens in this region of the spectrum. However, because of its peak emission at 667 nm, Alexa Fluor® 647 cannot be seen well by eye, and it cannot be excited optimally with a mercury lamp. Therefore, Alexa Fluor® 647 is not recommended for use with conventional epifluorescent microscopes. It is most commonly visualized with a confocal microscope equipped with an appropriate laser for excitation and a far-red detector. Alexa Fluor® 647 conjugates are less expensive alternatives to allophycocyanin conjugates for flow cytometry.



