Fig. 9. Application of furan-thiol-amine (FuTine) multicomponent reaction (MCR) in dual labeling of proteins and modification of proteins in cell lysate.

a Dual modification of a protein with two different fluorophores by two different strategies. First, selective labeling of tyrosine via phenyl diazonium salts generating diazo complexes followed by selective labeling of lysine via FuTine MCR. Independent gels were run twice for dual labeling of a protein. b Selective labeling of lysine or cysteine on proteins in a cell lysate using thiol-FITC or AZ680-amine dye (NH₂-AZ680) and oxidized furan as analyzed by in-gel fluorescence analysis (for lysine labeling-right side gel; for cysteine labeling-left side gel, lane 4). The reaction works only in the presence of all three components as no fluorophore labeling was observed with thiol or amine in the absence of oxidized furan (lanes 1–3). Independent gels were run twice for labeling cell lysate. Created with BioRender.com.