Ex/Em: 565/575 nm

Phycobilin is composed of many subunits, each of which has a protein skeleton to which the linear tetrapyrrole chromophore is covalently bound. Phycoglobin (red) and phycocyanin (blue) are the two main phycobilin proteins. Phycoglobin (PE) has a maximum absorption between 490 and 570 nm, while phycocyanin (PC) has a maximum absorption between 610 and 665 nm. In general, phycobilin has good long-term stability when stored in cold storage in a solution containing ammonium sulfate. Purified phycobilin may decompose into subunits under acidic or alkaline conditions, but is relatively stable at room temperature and in neutral solutions at concentrations greater than 0.1 mg/ml. The dissociated subunits generally have lower coloration and fluorescence than the natural pigments. It is recommended that all phycobilin and its conjugations (preferably in a neutral buffer solution) be stored refrigerated and not frozen.

Phycobilin proteins (including B-phycoglobin (B-PE), R-phycoglobin (R-PE), and allophycocyanin (APC)) are super-sensitive fluorescent dyes for biological detection. They are more than 100 times more sensitive than conventional organic fluorophores, even in practical applications such as flow cytometry and immunoassay. The sensitivity of phycobilin-bound antibodies is usually much higher than that of corresponding organic antibodies based on molecular conjugates. R-Phycoerythrin (R-PE) is isolated from red algae. Its main absorption peak is 565 nm, with secondary absorption peaks at 496 nm and 545 nm. The intensity of R-PE secondary peaks from different species was different. R-PE has three types of subunits: α (~20,000 Dalton), β (~20,000 Dalton), and γ (~30,000 Dalton). The molecular weight of intact R-PE has been found to be about 240,000 Daltons, and the subunit structure (αβ)6γ has been determined. The α subunits of R-PE contain only phycoglobin (PEB) chromophores, while the β and γ subunits contain PEB and phycocyanin (PUB) chromophores. The variation in the absorption spectra of R-PEs from different species is due to differences in the PEB/PUB ratio of the subunits. R-PE and B-PE are the most fluorescent phycobilic proteins with quantum efficiencies of over 90%.

Precautions

1. The product is in solution form, and the solution is a neutral buffer containing ammonium sulfate.

2. Keep the product at 4℃ and avoid freezing.

3. Fluorescent dyes have quenching problems, please try to avoid light to slow down fluorescence quenching.

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