Spectroscopic studies on the tyrosine residues of canavalin.
Canavalin is a tetramer with 6 tyrosines per subunit. In the work presented here, we have classified these tyrosines by their spectrophotometric and fluorometric pH titration and their ability to be quenched I-. Of the 6 residues, 2 were found to be exposed to the solvent. One (pK = 10.2) contributes 28% of the total fluorescence intensity; the second has a pK of 11.50, and a lower quantum yield, contributing only 16% of the total intensity. The remaining 4 residues (pK = 12.5, contributing 54% of fluorescence intensity) are buried; their titration is irreversible, requiring protein denaturation.
D055598:Chemical Phenomena; D002621:Chemistry; D007887:Fabaceae; D005916:Globulins; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D046911:Macromolecular Substances; D008433:Mathematics; D010940:Plant Proteins; D010946:Plants, Medicinal; D011489:Protein Denaturation; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014443:Tyrosine / Q000032:analysis
D005916:Globulins; D046911:Macromolecular Substances; D010940:Plant Proteins; D014443:Tyrosine