title: Nuclear antigens: characterization of the acidic nuclear ribonucleoprotein-Sm-antigen complex by analytical and preparative isoelectric focusing.
abstract: The soluble ribonucleoprotein nuclear antigen (RNP), associated with the Sm antigen and present in extracts of rabbit thymus acetone powder, was purified by ion-exchange chromatography. Analytical isoelectric focussing (IEF) showed two bands at pH 5.2 and two bands at pH 5.4. After treatment by RNAse these 4 bands disappeared, and a new band with a pI of 6.1, representing the intact protein moiety, appeared. During preparative IEF in granulated gels the antigenicity of RNP was lost. Only the Sm antigen could be detected by counter-immunoelectrophoresis. Fractions with Sm antigenicity refocussed as two intense bands (pI 6.8 and 7.2) and one or two fainter bands (pI 6.1). On reducing SDS-PAGE the SM antigen revealed two bands of apparent molecular weights of about 110,000 and 28,500, indicating a total molecular weight of 138,500.
mesh_terms: D000818:Animals; D000941:Antigens / Q000302:isolation & purification*; D002868:Chromosomal Proteins, Non-Histone / Q000302:isolation & purification*; D006801:Humans; D007525:Isoelectric Focusing / Q000379:methods*; D009698:Nucleoproteins / Q000276:immunology*; D011817:Rabbits; D012261:Ribonucleoproteins / Q000276:immunology*; D013949:Thymus Extracts / Q000032:analysis
chemical_list: D000941:Antigens; D002868:Chromosomal Proteins, Non-Histone; D009698:Nucleoproteins; D012261:Ribonucleoproteins; D013949:Thymus Extracts