Fluorescent Chromeo™ Py-Dyes
Fluorescent-Chromeo-Py-Dyes-AM545
Synonyms
| Name | Format | Cat No. | Price |
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Overview
Chromeo™ Py-Dyes are a unique class of amine-reactive pyrylium dyes that change their color and become fluorescent upon reacting with primary amines. The shift in absorption and the induction of fluorescence effectively eliminate background effects from any unbound dye. The labeled proteins are ready to use immediately, and as the labeling method is fast, easy & reproducible, Chromeo Py-Dyes are suitable for a variety of “no-wash” applications:
Chromeo Py-Dyes have been shown to work efficiently and with high sensitivity in different methods of protein electrophoresis. Proteins labeled with pyrylium dyes maintain their native charge and isoelectric points, which results in sharp and characteristic bands during electrophoresis.
Description
Pyrylium dyes change their color and fluorescent properties upon reacting with proteins. After binding to primary amines, they undergo a large shortwave spectral shift that is visible to the naked eye (Figure 1). There is also a large increase in quantum yield that changes the non- or only weakly fluorescent dye into a bright fluorescent conjugate. (See the Properties tab for detailed information on each Py-Dye).
Figure 1: Color shift of Chromeo Py-Dyes caused by dye conjugation.Chromeo P503 is blue while in its free state. After the short conjugation reaction, the dye's color undergoes a large Stokes shift and becomes red.
The shift of the absorption & emission bands together with the increased fluorescence quantum yield effectively eliminates background from any unbound dye. In addition, because unbound pyrylium dye is hydrolyzed during the labeling procedure, there is no need for purification following the simple one-step, room-temperature incubation. The labeled protein is ready to use immediately, and any possible background from unbound dye is eliminated. Due to the unique conjugation mechanism, proteins labeled with Py-Dyes maintain their native charge and isoelectric point. This is an important improvement over other derivatization-based methods for labeling proteins because it eliminates band or peak broadening in different assays and maintains the native characteristics of the proteins.
Chromeo™ Py-Dye advantages
- No washing steps required
- No background from unbound dye
- Fast and simple procedure
- Small size
- No change in net charge of the labeled molecule
- No interference of excitation and emission wavelength
Because of their unique features, Chromeo Py-Dyes (Chromeo P429, P503, P540 and P543) have been used successfully in a number of “no-wash” applications such capillary electrophoresis, SDS-protein gel electrophoresis, isoelectric focusing or as a label in receptor binding studies. See the Product Citations tab for a sample of published references.
Properties
| Dye | Dye State | Absorption | Emission | ε L/(mol-cm) | Quantum Yield* |
|---|---|---|---|---|---|
| Chromeo™ P503 | Free | 612 nm | 665 nm | 60,000 | < 1% |
| Conjugated | 503 nm | 600 nm | 24,000 | ~50% | |
| Chromeo™ P540 | Free | 587 nm | – | 80,000 | 0% |
| Conjugated | 533 nm | 627 nm | 50,000 | ~20% | |
| Chromeo™ P429 | Free | 457 nm | – | 65,000 | 0% |
| Conjugated | 429 nm | 536 nm | 75,000 | ~10% | |
| Chromeo™ P543 | Free | 570 nm | – | 110,000 | 0% |
| Conjugated | 543 nm | 590 nm | 57,000 | ~15% | |
| Table 1: Properties of Chromeo Py-Dyes. *Quantum Yield will depend on the DPR of the conjugated protein. |
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Contents
Contents & Storage
Each Chromeo Py-Dye is supplied as a dry powder. Guaranteed stable for 6 months when stored properly.