A supramolecular approach to protein labeling. A novel fluorescent bioassay for concanavalin a activity.

[reaction: see text] A new method for the bioassay of concanavalin A is based on the interaction of saccharide-substituted oligopyrrolic macrocycles with lectins. A general sensing mechanism involves the interaction of aggregated and primarily nonfluorescent labels with the target protein, label deaggregation, site-specific binding, and fluorescence signaling. Addition of saccharides to the fluorescent lectin-macrocycle complex leads to the release of the label and partial quenching of fluorescence due to reaggregation. Specificity of the protein-probe binding is discussed.