PB-PEG4-Acid is an intense, blue-fluorescent dye with an excitation at 410 nm and emission at 455 nm. The hydrophilic PEG chains increase the water solubility of a compound in aqueous media. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond. Reagent grade, for research purpose. Please contact us for GMP-grade inquiries.