title: The isolation and characterization of the V-H domain from rabbit heavy chains of different a locus allotype.
abstract: The Fd fragment of rabbit gamma-chains was split by papain to yield a smaller fragment with a molecular weight of approximately 14,000 and dialyzable small peptides and amino acids. The domain size fragment was identified as intact variable region from its amino acid content, its blocked amino-terminus, and two characteristic cysteine-containing peptides, while the small peptides and amino acids were accounted for by the degradation of the C-H1 region. The variable regions isolated from Aa1 and Aa3 Fd fragments not only reacted quantitatively with immunoadsorbents conjugated with the homologous anti-a allotype antibody, but also completely inhibited the binding of the parent Fd fragment to the homologous antibody as measured by radioimmune assay. These data provide direct evidence that the group a allotypic determinants are contained entirely in the variable portion and are independent of the constant portion of rabbit heavy chains.
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D002250:Carbon Radioisotopes; D002850:Chromatography, Gel; D002918:Chymotrypsin; D003574:Cytochrome c Group; D004226:Dithioerythritol; D004591:Electrophoresis, Polyacrylamide Gel; D007140:Immunoglobulin Fab Fragments / Q000302:isolation & purification; D007128:Immunoglobulin Fragments / Q000302:isolation & purification*; D007143:Immunoglobulin Heavy Chains / Q000302:isolation & purification*; D007457:Iodine Radioisotopes; D007461:Iodoacetates; D007519:Isoantigens / Q000302:isolation & purification*; D007785:Lactose; D010206:Papain; D010434:Pepsin A; D010455:Peptides / Q000032:analysis; D010544:Peroxidases; D011817:Rabbits; D011863:Radioimmunoassay; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D003574:Cytochrome c Group; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments; D007143:Immunoglobulin Heavy Chains; D007457:Iodine Radioisotopes; D007461:Iodoacetates; D007519:Isoantigens; D010455:Peptides; D014316:Tritium; D004226:Dithioerythritol; D010544:Peroxidases; D002918:Chymotrypsin; D010206:Papain; D010434:Pepsin A; D007785:Lactose