Fluorescent Chameleon Labels for Bioconjugation and Imaging of Proteins, Nucleic Acids, Biogenic Amines and Surface Amino Groups. A Review.

Chameleon labels (ChLs) possess the unique property of changing (visible) color and fluorescence on binding to amino groups of biomolecules. Some ChLs react with primary aliphatic amino groups such as those in lysine or with amino groups artificially introduced into polynucleic acids or saccharides, while others also react with secondary amino groups. Under controlled circumstances, the reactions are fairly specific. The review is subdivided into the following sections: (1) An introduction and classification of fluorescent labels; (2) pyrylium labels that undergo shortwave color changes upon labelling, typically from blue to red; (3) cyanine type of labels (that also undergo shortwave color changes, typically from green to blue; (4) various other (less common) ChLs; (5) hemocyanine labels that undergo longwave color changes, typically from yellow to purple; (6) the application of various ChLs to labeling of proteins and amino-modified saccharides and oligonucleotides; (7) applications in fluorometric assays and sensing; (8) in fluorescence imaging of biomolecules; (9) in studies on affinity interactions (receptor-ligand binding); (10) in surface and interface chemistry; and (11) in chromatography, electrophoresis and isotachophoresis of biomolecules. This review cites 108 references.