APDye Fluor 660 is a bright and photostable near-infrared dye with nearly the same spectrum as Alexa Fluor® 660 and CF660® 680RD. APDye Fluor 680 typically excites well-suited 633 or 647 nm laser lines for bright and photostable far-red dyes. APDye Fluor 660 is ideal for 633 nm laser lines. This near-infrared fluorescent dye is water-soluble and pH-insensitive in the pH 4 to pH 10 range. APDye Fluor 660 molecules can be attached to proteins at high molar ratios without significant self-quenching, resulting in brighter conjugates and more sensitive detection. Long wavelength emission allows detection in complex samples with autofluorescent background signals. The carboxylic acids of APDye Fluor 660 are the reagents of choice for the preparation of custom reactive esters that are not typically commercially available. Examples of such activated esters include sulfo-NHS, TFP (2,3,5,6-tetrafluorophenol), STP (4-sulfo-2,3,5,6-tetrafluorophenol, sodium salt). Another common application of non-activated carboxylic acids is peptide modification during solid-phase synthesis, which often requires in situ activation using peptide coupling reagents such as HATU.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.