Description

Phycobiliproteins are fluorescent proteins derived from cyanobacteria and eukaryotic algae. Their fluorescence is much higher than chemical fluorescent probes such as fluorescein and rhodamine. R-Phycoerythrin (R-PE) is one of the phycobiliproteins and has a red fluorescence at around 578 nm, and it can be excited at 488nm (Fig. 1). Because of this high fluorescence, phycobiliprotein labeled antibodies, and other molecules can provide greater sensitivity in flow cytometry and immunostaining. R-phycoerythrin Labeling Kit-NH₂ is for simple and rapid preparation of R-PE-labeled IgG (Fig. 2). NH₂-reactive R-PE (a component of this kit) has an activated ester group and can easily make a covalent bond with an amino group of the target molecule without any activation process. The filtration tube in this kit allows a quick buffer exchange and concentration of sample IgG solution. This kit contains all of the reagents necessary for R-PE labeling, including the Storage buffer for conjugates.

Fig. 1 Fluorescence spectrum of R-PE
Excitation wavelength: 566 nm
Emission wavelength: 578 nm

Fig. 2 IgG labeling reaction of NH₂-reactive R-PE

Precaution
♦ The molecular weight of the protein to be labeled with this kit should be greater than 50,000.
♦ IgG or R-phycoerythrin-conjugated IgG is always on the membrane of the filtration tube during the labeling process.
♦ If the IgG solution contains other proteins with molecular weight larger than 10,000, such as BSA or gelatin, purify the IgG solution prior to labeling R-phycoerythrin with this kit. 
♦ If the IgG solution contains small insoluble materials, centrifuge the solution and use the supernatant for the labeling.