title: Biophysical and biochemical heterogeneity of purified hepatitis B antigen.
abstract: Hepatitis B antigen of the D (a+, d+, y-) subtype was purified from plasma of apparently healthy persons and from hepatitis patients. The original samples contained 20- and 42-nm particles and tubular forms (20-nm diameter). Ultracentrifugation during the purification procedure yielded pellets which were then treated at pH 2.4. Both the large, 42-nm Dane particles and the tubular forms were lost during the acid treatment of the pelleted particles, yielding a preparation containing a mixture of particles approximately 20 and 25 nm in diameter. This difference in size was substantiated in that two distinct molecular weights were calculated from high-speed equilibrium data, 3.6 x 10(6) and 4.5 x 10(6). Further heterogeneity was observed in that hepatitis B antigenic activity was present in purified particles with an isoelectric pH of 4.0 and also in those with a pH of 4.4. No significant differences were observed in the gross amino acid composition of purified antigen obtained from plasma of three different persons. (125)I-labeled, purified antigen was found to contain six distinct polypeptides with molecular weights ranging from 10,000 to 39,000.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D006506:Hepatitis A / Q000097:blood; D006511:Hepatitis B Antigens / Q000032:analysis / Q000302:isolation & purification*; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D007456:Iodine Isotopes; D007525:Isoelectric Focusing; D008854:Microscopy, Electron; D008970:Molecular Weight; D010772:Phosphotungstic Acid; D011863:Radioimmunoassay; D013194:Staining and Labeling; D014764:Viral Proteins / Q000032:analysis
chemical_list: D000596:Amino Acids; D006511:Hepatitis B Antigens; D007456:Iodine Isotopes; D014764:Viral Proteins; D010772:Phosphotungstic Acid