Biosynthesis of the carbohydrate portion of immunoglobulins. Incorporation of radioactive fucose into immunoglobulin G1 synthesized and secreted by mouse plasma-cell tumour MOPC 21.
Incorporation of radioactive fucose into the immunoglobulin G1 myeloma protein secreted by mouse plasma-cell tumour MOPC 21 is stereospecific for the l-isomer. Heavy chains of the secreted form of the myeloma protein carry 90% of the label in fucose residues of their carbohydrate moieties. A small but significant amount of the intracellular immunoglobulin G1 of the mouse plasma-cell tumour MOPC 21 appears to be labelled. Serum in the incubation medium supplies low-molecular-weight diffusible substances necessary to maintain continuous secretion of fucose-labelled myeloma protein beyond 2-3h, and of leucine-labelled myeloma protein beyond 6-8h. In medium containing extensively dialysed serum the secretion of leucine- and fucose-labelled myeloma protein can be restored by the addition of 250mum-d-mannose, 250mum-d-galactose and 250mum-glucosamine. Synthesis and secretion appear to be facilitated in the presence of these sugars, although secretion of myeloma protein devoid of terminal fucose residues is possible for a limited time-period.
D000818:Animals; D002241:Carbohydrates / Q000096:biosynthesis*; D002247:Carbon Isotopes; D002417:Cattle; D003956:Dialysis; D005643:Fucose / Q000378:metabolism*; D005690:Galactose; D005944:Glucosamine; D007074:Immunoglobulin G / Q000096:biosynthesis; D007136:Immunoglobulins / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007930:Leucine / Q000378:metabolism; D008358:Mannose; D051379:Mice; D008970:Molecular Weight; D009374:Neoplasms, Experimental / Q000378:metabolism; D010954:Plasmacytoma / Q000378:metabolism*; D013237:Stereoisomerism; D013997:Time Factors; D014316:Tritium
D002241:Carbohydrates; D002247:Carbon Isotopes; D007074:Immunoglobulin G; D007136:Immunoglobulins; D014316:Tritium; D005643:Fucose; D007930:Leucine; D005944:Glucosamine; D008358:Mannose; D005690:Galactose