Many applications and instruments were developed specifically for R-phycoerythrin. It is commonly used in immunoassays such as FACS, flow cytometry, multimer/tetramer applications. With new instrumetation available, R-PE is also well suited for immunohistochemistry (IHC) and Western blot applications.
Structural Characteristics
R-phycoerythrin is predominantly produced by red algae. The protein is made up of at least three different subunits and varies according to the species of algae that produces it. The subunit structure of the most common R-PE is (αβ)6γ. The α subunit has two phycoerythrobilins (PEB), the β subunit has 2 or 3 PEBs and one phycourobilin (PUB), while the different gamma subunits are reported to have 3 PEB and 2 PUB (γ1) or 1 or 2 PEB and 1 PUB (γ2). The molecular weight of R-PE is 250,000 Daltons.
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Excitation and emission profiles for SureLight® R-PE versus alternate source R-PE at a standard protein concentration. (Emission scan excitation wavelength at 488 nm.)
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Comparative emission levels of SureLight® R-PE versus alternate source R-PE at common instrument laser excitation wavelengths at a standard protein concentration. Excitation wavelengths correspond to :
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Spectral Characteristics
| Absorption maximum | 565 nm |
| Additional Absorption peak | 498 nm |
| Emission maximum | 573 nm |
| Extinction Coefficient (ε) | 1.96 x 106 M-1cm-1 |
| Quantum Yield (QY) | 0.84 |
| Brightness (ε x QY) | 1.65 x 106 M-1cm-1 |
Specifications
| A566/A280 ≥ 5.0 |
| A566/A498 < 1.5 |
| A620/A566 < 0.01 |
| Functional activity Relative QY > 2.50 |
| >98% single peak by HPLC |