Cy5-PEG4-acid is a carbonyl reactive building block used to modify carboxylic groups in the presence of activators (e.g. EDC, or DCC) or activated esters (e.g. NHS esters) through a stable amide bond. It also can be employed as a polar tracer and as a reactive dye for labeling proteins via a carboxylic acid moiety.
Cy5-PEG4-acid is a water-soluble, bright, far-red-fluorescent probe with excitation ideally suited for the 633 nm or 647 nm laser lines. A significant advantage to using long wavelength dyes such as Cy5 or AF 647 dye over other fluorophores is the low autofluorescence of biological specimens in this region of the spectrum.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.