Labelling

Biotin-SS-Sulfo-Osu is used as the biotin labeling agent for the amino groups of proteins such as antibodies and enzymes.

Biotin-PE-maleimide is used as the biotin labeling agent.

IC<sub>5<sub>-OSu special packaging is ued as fluorescent labeling reagent. IC5 is an indocyanine dye that can react with amine groups on proteins, peptides, and amine-modified oligonucleotides. Due to the absence of a sulfonate group in its structure, the water-solubility of the molecules is very low, necessitating the use of an organic solvent for dissolution. Furthermore, as no negative charge is added to the protein, the total number of charges on the modified protein remains the same before and after labeling with these compounds.

Biotin-(AC<sub>5<sub>)<sub>2<sub>-OSu is utilized as the biotin labeling agent in the Biotin Labeling Kit-NH<sub>2<sub>.

Cy7.5 NHS ester is a water soluble fluorescent dye with a terminal NHS ester group. Cy7.5 NHS ester is a near-infrared (NIR) dye known for its long-wave emission. It serves as an amine-reactive derivative, ideal for labeling biomolecules like proteins and peptides for in vivo NIR imaging.

Ald-Ph-PEG8-t-butyl ester is a PEG linker containing a benzaldehyde and a t-butyl ester. The aldehyde group is a versatile electrophile that is reactive towards amines, hydroxylamines, and hydrazines while the t-butyl ester can be removed to reveal a carboxylic acid that can react with alcohols or amines.

BP Fluor 647 NHS Ester is a very popular amine-reactive fluorescent dye which can be used to label antibody, protein, and other biomolecules. BP Fluor 647 is a red fluorescent dye with excitation and emission maxima at 648 nm and 671 nm respectively.

DNP-PEG12-azide is a heterobifunctional PEG linker featuring a dinitrophenyl and a primary amine. Dinitrophenyl is an excellent FRET quencher pair with tryptophan or tyrosine, while the azide can be used in click chemistry with terminal alkynes or strained cyclooctynes.

Fluorescein-PEG12-amine, TFA salt is a PEG linker containing an amine and a fluorescein dye. Primary amines readily form amides with carboxylic acids in the presence of reagents such as HATU or EDC while fluorescein is a fluorophore is a near-UV/Vis spectrum dye that can be used for in vivo fluorescence assays such as FRET.