Hemicyanine dyes derived from 2,3,3-trimethyl-3H-indolium as candidates for non-covalent protein probes.

Non-covalent interaction of hemicyanine dyes, derivatives of 2,3,3-trimethyl-3H-indolium with bovine serum albumin has been studied by spectral method. For this purpose, three hemicyanine dyes containing N-(2-carboxyethyl)-2,3,3-trimethyl-3H-indolium moiety were synthesized and their UV/Vis and fluorescence spectra, aggregation, photostability and association with bovine serum albumin were studied. The hemicyanine dyes with 2-ethylcarboxylic group was found to interact with bovine serum albumin, which is probably due to negative charge on the dye molecule at the expense of the carboxylic group and the ability to form hydrogen bonds with albumin.