title: Identification and properties of J chain isolated from catfish macroglobulin.
abstract: After the cleavage of disulfide bonds of macroglobulin isolated from channel catfish (Ictalurus punctatus), an electrophoretically fast-moving polypeptide, which resembled human J chain, was released. On a Sephadex G-200 column equilibrated in 5 M guanidine, the elution position of the J chain overlapped with the descending part of the L chain peak. Further purification was achieved by DEAE ion-exchange chromatography. The isolated polypeptide, which had a molecular weight of 14,800 +/- 500, as determined ultracentrifugally by sedimentation equilibrium in 5 M guanidine, contained 7% carbohydrate with one residue of fucose, two of mannose, one of galactose, two of glucosamine, and one of sialic acid per chain. A comparison of catfish and human J chain amino acid analyses showed the former to have a higher content of serine, glycine, and phenylalanine and a lower content of aspartic acid, isoleucine, and arginine. Tryptic peptide maps of catfish and human J chains revealed very few common peptides. Rabbit and guinea pig antisera to human J chain did not cross-react with catfish J chain. Untreated, resuced and alkylated, S-sulfonated, or cyanogen bromide cleaved macroglobulin from the gar (Lepisosteus osseus) contained no polypeptide analogous to either catfish or human J chain by the criteria employed in this study.
mesh_terms: D000085:Acetates / Q000032:analysis; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004220:Disulfides / Q000378:metabolism; D004589:Electrophoresis, Disc; D005399:Fishes / Q000276:immunology*; D005643:Fucose / Q000032:analysis; D005690:Galactose / Q000032:analysis; D005944:Glucosamine / Q000032:analysis; D006168:Guinea Pigs; D006801:Humans; D007106:Immune Sera / Q000032:analysis; D007143:Immunoglobulin Heavy Chains / Q000302:isolation & purification; D007144:Immunoglobulin J-Chains / Q000032:analysis* / Q000302:isolation & purification*; D007147:Immunoglobulin Light Chains / Q000302:isolation & purification; D008259:Macroglobulins / Q000032:analysis*; D008358:Mannose / Q000032:analysis; D010446:Peptide Fragments / Q000302:isolation & purification; D010455:Peptides / Q000302:isolation & purification; D011817:Rabbits; D012794:Sialic Acids / Q000032:analysis; D014461:Ultracentrifugation
chemical_list: D000085:Acetates; D000596:Amino Acids; D004220:Disulfides; D007106:Immune Sera; D007143:Immunoglobulin Heavy Chains; D007144:Immunoglobulin J-Chains; D007147:Immunoglobulin Light Chains; D008259:Macroglobulins; D010446:Peptide Fragments; D010455:Peptides; D012794:Sialic Acids; D005643:Fucose; D005944:Glucosamine; D008358:Mannose; D005690:Galactose