Fluorescent Labeling of Protein Using Blue-Emitting 8-Amino-BODIPY Derivatives

8-Amino-BODIPY (boron-dipyrromethane) dyes show bright blue fluorescence. Disclosed here are synthesis and characterization of the photophysical properties of a series of functionalized 8-Amino-BODIPY (BP1–4) for protein labeling. The compact structure and solvent-insensitive absorption property of the dye are desirable features for protein labeling. For the model protein, bovine serum albumin (BSA), the labeling proceeds under mild condition via amide bond formation or thiol-ene conjugation with maintaining the bright blue fluorescence. The chromatography and mass spectroscopy analysis clearly support the labeling of the BODIPY dye on the BSA. The protein labeling with blue-emitting BODIPY would be applicable for studying protein dynamics and fluorescence resonance energy transfer (FRET) with intrinsic biomolecules.