Cy5-Yne is a clickable azido-reactive fluorescent probe.[1] It displays excitation/emission maxima of 650/680 nm, respectively. When conjugated to peptides, Cy5-Yne has been used as a pH-independent fluorescent probe for the activity of lysosomal cathepsin proteases in S. typhimurium-infected and bystander bone marrow-derived macrophages (BMDMs).
References:
[1].Sanman, L.E., van der Linden, W.A., Verdoes, M., et al.Bifunctional probes of cathepsin protease activity and pH reveal alterations in endolysosomal pH during bacterial infectionCell Chem. Biol.23(7)793-804(2016).