Visible fluorescence protein labeling kits can be used to label antibodies and other proteins for applications such as flow cytometry, microscopy, immunohistochemistry, and other applications where fluorophore-conjugated antibodies are required.
The visible dyes included in these kits are activated with N-hydroxysuccinimide (NHS) esters, which is the most commonly used reactive group for labeling proteins. NHS esters react with primary amines, forming stable, covalent bonds.
VRDye™ labeling kits are based on a simple conjugation protocol that uses fast, spin column cleanup with resulting purity equivalent to purification by dialysis. Raise the pH of the preservative-free protein solution with the provided buffer, combine it with the appropriate amount of water-soluble amine-reactive dye, and separate the labeled conjugate from the free dye using the included spin columns. Labeling and purification are complete in approximately 2 hours.
| Dye | Absmax | Emmax | ε (M-1cm-1) | MW (g/mole) | CF* |
|---|---|---|---|---|---|
| VRDye 549 | 550 | 575 | 150,000 | 1,040 | 0.07 |
| VRDye 490 | 491 | 515 | 73,000 | 1,011 | 0.11 |
*CF is a correction factor for the absorbance of the dye at Absmax to the absorbance of the protein at 280 nm.
