Cy5 NHS ester

Cy5 NHS ester(Cyanine5 NHS ester) is a Red emitting fluorescent dye for labeling of amino-groups in peptides, proteins, and oligonucleotides^[1]. The excitation and emission at 646 and 669nm, respectively^[2].

Cy5 NHS ester solution at 10 mg/ml in DMSO.Cy5 NHS ester amine-reactive red emitting fluorescent dye was used to react with the free amino group on the cysteine amino acid present in terminal peptides used for end-capping pBAEs backbones^[1].On the other hand， 1mg of Cy5 NHS ester dye was dissolved in 0.1ml of 62.5mM sodium tetraborate buffer (pH 8.5). After adding L-methionine in saturation, the mixture was incubated overnight at 4°C. Fluorophore (Cy5)-conjugated methionine (Cy5-Met) was purified by reverse-phase chromatography on an Agilent HPLC system using a C18 column^[3].

References:
[1].Brugada-Vilà P, Cascante A, et al. Oligopeptide-modified poly(beta-amino ester)s-coated AdNuPARmE1A: Boosting the efficacy of intravenously administered therapeutic adenoviruses. Theranostics. 2020 Feb 3;10(6):2744-2758.
[2].Jiménez Sánchez G, et al. Fluorescent Radiosensitizing Gold Nanoparticles. Int J Mol Sci. 2019 Sep 18;20(18):4618.
[3].Kim JM, Seong BL. Highly chromophoric Cy5-methionine for N-terminal fluorescent tagging of proteins in eukaryotic translation systems. Sci Rep. 2017 Sep 14;7(1):11642.