title: An abnormal human IgA1 half-molecule.
abstract: An IgA1 half-molecule, which is composed of a deleted alpha1 chain linked with a disulfide bond to an intact kappa chain, was detected in a patient (Cha). The molecular weights of the paraprotein and the isolated alpha1 chain were estimated to be 75 000 and 53 000, respectively. Identification of tyrosine as the C-terminal amino acid and the presence of idiotypic determinants in the abnormal alpha1 chain indicated that the molecule would have an intact N-terminal variable region and a C-terminal region. Furthermore, no cleavage of the abnormal protein into Fab and Fc by proteolytic enzyme isolated from Neisseria gonorrhoeae suggested the absence of a "hinge" region in the abnormal alpha1 chain.
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002872:Chromosome Deletion; D006801:Humans; D007070:Immunoglobulin A / Q000235:genetics; D007126:Immunoglobulin Allotypes; D007143:Immunoglobulin Heavy Chains; D007137:Immunoglobulin alpha-Chains; D007145:Immunoglobulin kappa-Chains; D008970:Molecular Weight; D009344:Neisseria gonorrhoeae / Q000201:enzymology; D010447:Peptide Hydrolases / Q000378:metabolism
chemical_list: D007070:Immunoglobulin A; D007126:Immunoglobulin Allotypes; D007143:Immunoglobulin Heavy Chains; D007137:Immunoglobulin alpha-Chains; D007145:Immunoglobulin kappa-Chains; D010447:Peptide Hydrolases