title: Properties and subunit characterization of affinity purified Sophora japonica lectin.
abstract: The affinity purified Sophora japonica lectin exhibits an anomalous behavior on polyacrylamide gel electrophoresis (PAGE). Electrophoresis at pH 8.9 produces three protein staining bands. Extraction and re-electrophoresis of the fastest and slowest migrating components demonstrates that the lectin solution is an equilibrium mixture of interconvertible forms. Addition of a bindable saccharide, D-galactose, during PAGE causes the equilibrium to be shifted toward a single form. As indicated by analytical gel filtration, sedimentation velocity ultracentrifugation and ion-exchange chromatography experiments, the equilibrium mixture consists of charge and not molecular weight variants of the native molecule of 132,800 g/m. Results from end-group and cysteine analyses and PAGE in sodium dodecyl sulfate indicate that the native lectin is composed of the non-covalent association of two dissimilar subunits. One subunit consists of two identical polypeptide chains attached by two disulfide bonds and the other subunit of two identical polypeptide chains stabilized by a single cysteine bridge.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005690:Galactose; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000032:analysis* / Q000302:isolation & purification; D008623:Mercaptoethanol; D008970:Molecular Weight; D037121:Plant Lectins; D010944:Plants / Q000032:analysis*; D014461:Ultracentrifugation / Q000379:methods
chemical_list: D037102:Lectins; D037121:Plant Lectins; D008623:Mercaptoethanol; D005690:Galactose