title: The optical properties of alpha 2-macroglobulin from normal and from cystic fibrosis plasma.
abstract: The alpha 2-macroglobulin (alpha 2-M) was purified from the plasma of normal individuals and from that of cystic fibrosis patients. The proteins exhibited identical optical properties. Both proteins have an absorbance coefficient of A = 1060 g . cm-2 at 280 nm. The circular dichroism spectra are identical and indicate about 45% beta-sheet structure and almost no alpha-helix. The spectra of solutions at pH 8.0 do not change when trypsin is added. The fluorescence spectra of the alpha 2-M measured at pH 8.0 have contributions by tyrosine and tryptophan residues. The fluorescence intensities are identical and are enhanced about 30% when trypsin is added in 2:1 molar ratios.
mesh_terms: D002942:Circular Dichroism; D003550:Cystic Fibrosis / Q000097:blood*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D013050:Spectrometry, Fluorescence; D014357:Trypsin; D000511:alpha-Macroglobulins / Q000302:isolation & purification
chemical_list: D000511:alpha-Macroglobulins; D014357:Trypsin