Charge forms of serum and whey transferrin in rat differ in the sialic acid content of their glycan chains: immunological implications.
Transferrin has been purified from both rat whey and rat serum. Both proteins migrated as the same size on electrophoresis in the presence of sodium dodecyl sulphate but when electrophoresed under native conditions showed the presence of multiple charge forms. The patterns observed were not altered by iron binding or removal and all forms were shown to bind iron. Treatment with neuraminidase tended to condense all bands into a single species common to both transferrins whereas treatment with a peptide N-glycosidase resulted in a complex pattern of bands consistent with removal of one of the two glycan chains of the transferrins. A sensitive enzyme-linked immunosorbent assay (ELISA) was set up to examine the transferrins. Iron binding and removal and treatment with peptide N-glycosidase all modified the ELISA signal obtained. Neuraminidase, however, did not affect the ELISA signal.
Donaldson
A B
AB
Department of Biochemistry, University of Otago, Dunedin, New Zealand.
Grigor
M R
MR
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D007120:Immunochemistry; D007501:Iron / Q000378:metabolism; D008894:Milk Proteins / Q000737:chemistry* / Q000276:immunology; D011134:Polysaccharides / Q000737:chemistry*; D051381:Rats; D011919:Rats, Inbred Strains; D012794:Sialic Acids / Q000032:analysis*; D014168:Transferrin / Q000737:chemistry* / Q000276:immunology
D008894:Milk Proteins; D011134:Polysaccharides; D012794:Sialic Acids; D014168:Transferrin; D007501:Iron