title: The S100-b protein: tyrosine residues do not exhibit an abnormal fluorescence spectrum.
abstract: The beta subunit of the bovine brain S100-b protein (beta beta) lacks tryptophyl residue but contains one tyrosine. Our experiments show that this protein is characterized by a typical tyrosine fluorescence spectrum, with a maximum at 303 nm. Identical fluorescence properties were found for the rat brain S100-b protein. Comparison with the fluorescence spectrum of the bovine brain S100-a' protein (alpha'beta), which contains a tryptophan residue in the alpha' subunit, enables us to demonstrate that the recent report describing an abnormal fluorescence spectrum for the bovine brain S100-b protein may result from a contamination of the S100-b by the S100-a' protein.
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D046911:Macromolecular Substances; D008970:Molecular Weight; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000032:analysis*; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014443:Tyrosine / Q000032:analysis*
chemical_list: D046911:Macromolecular Substances; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D014443:Tyrosine