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:
○Pre- and post-stain in SDS-protein electrophoresis
○Pre-stain in capillary electrophoresis (CE)
○Pre-stain in capillary isoelectric focusing (IEF)
○Pre-stain in 2D capillary electrophoresis
○Label for carbohydrate characterization
○Small size label of proteins
○Reagent to monitor amino functionalities on various surfaces
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. For your convenience, Chromeo Py-Dyes are also included in our complete Capillary Electrophoresis (CE) Dye Kits, containing optimized and quality-controlled buffer systems.
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).
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
○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, P456, 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.