Technical Information on R-Phycoerythrin Conjugated Fab Fragments

Phycoerythrin and other phycobiliproteins are well characterized when used as conjugates (usually coupled to antibodies) in fluorescent immunoassays. They possess many fluorescent groups per protein resulting in large extinction coefficients and high quantum yields. Other desirable characteristics are:                                                    
Emission in the orange-red end of the spectrum, where background fluorescence is lower. Fluorescence yields are constant over a broad pH range. Fluorescence not quenched by naturally occurring biological substances.              
High solubility and stability in aqueous solutions.

PROTOS IMMUNORESEARCH provides Fab fragments of secondary antibodies, coupled to R-Phycoerythrin (R-PE).  Fab fragments were chosen since they are well suited to be covalently coupled to R-PE, while preserving antibody activity. In addition, absence of the Fc part will avoid Fc-mediated non-specific binding to cells and tissues. On average, between two and three molecules of Fab are coupled to one R-PE molecule. Due to the coupling technique used, larger complexes are avoided, resulting in very low background levels.

R-PE         :  Mol.Weight 240,000 dalton

Absorption :  488 nm ; Emission : 575 nm

Conjugate   :  0.2 mg/ml

Buffer         :  PBS, pH 7.2, 1% BSA, 15 mM sodium azide (preservative)

Application :  Stain 1 Million cells in Flow Cytometry with 1 mg conjugate . (lesser amounts may be sufficient)



Protos Immunoresearch

875A Cowan Road, Burlingame, CA 94010

Tel: 650 652-3450      Fax: 650 652-3451


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