title: Immunochemical studies on alpha-lactalbumin.
abstract: The antigenic structural features of alpha-lactalbumin have been investigated using a radioimmunoassay, peptide inhibition of the quantitative precipitin reaction, and by immunodiffusion analysis after chemical modification of the molecule. Antigenic activity (in rabbits) was localized to several peptic fragments and the single arginine residue of bovine alpha-lactalbumin. Antigenic activity was also found to be associated with the single methionine residue. A peptic fragment containing a disulfide loop was found to possess antigenic activity in both bovine and goat alpha-lactalbumin. Radioimmunoassay cross-reactivity between the alpha-lactalbumins is correlated with amino acid sequence similarities; bovine alpha-lactalbumin antiserum cross-reacts with goat alpha-lactalbumin more extensively than with human alpha-lactalbumin, while the more distantly homologous protein, chicken lysozyme, does not cross-react at all. Nevertheless our data indicate that the alpha-lactalbumins and lysozyme share a similar distribution of antigenic determinants on their surfaces.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000941:Antigens / Q000032:analysis*; D002417:Cattle; D003429:Cross Reactions; D000939:Epitopes / Q000032:analysis; D006041:Goats; D005779:Immunodiffusion; D007768:Lactalbumin / Q000276:immunology*; D008715:Methionine / Q000276:immunology; D010446:Peptide Fragments / Q000302:isolation & purification; D011233:Precipitin Tests; D011817:Rabbits; D011863:Radioimmunoassay
chemical_list: D000596:Amino Acids; D000941:Antigens; D000939:Epitopes; D010446:Peptide Fragments; D007768:Lactalbumin; D008715:Methionine