Description General description Atto 611X belongs to a new generation of fluorescent labels invented by ATTO-TEC. The dye is designed for application in the area of life science, e.g. labeling of DNA, RNA or proteins. Characteristic features of the label are strong absorption, high fluorescence quantum yield, exceptionally large Stokes-shift, high photostability, good water solubility, and very little triplet formation. Atto 611X is a pH sensitive product. Above pH 5.0 it exists in an equilibrium with a colorless form. However, this reversible reaction does not interfere with the process of coupling to protein etc. Maleimides are well suited for coupling to thiol groups. This is similar to iodacetamides, but maleimides do react more thiol selective. They do not show significant reaction with histidine or methionine. Hydrolysis of maleimides to a mixture of isomeric nonreactive maleamic acids can compete significantly with thiol modification, particularly above pH 8. Maleimides may be used for labelling of amines, which usually requires a higher pH than reaction of maleimides with thiols. After coupling to a substrate the label carries a net electrical charge of -1. find more information here Packaging Bottomless glass bottle. Contents are inside inserted fused cone.