US Patent RE39663 Electron-deficient nitrogen heterocycle-substituted fluorescein dyes

The invention provides compositions electron-deficient nitrogen heterocycle-substituted fluorescein dyes and methods in which the dyes are conjugated to substrates and used as detection labels in molecular biology experiments. The electron-deficient nitrogen heterocycles include pyridine, quinoline, pyrazine, and the like. Substrates include polynucleotides, nucleosides, nucleotides, peptides, proteins, carbohydrates, and ligands.