Iron-binding fragments from the carboxyl-terminal region of hen ovotransferrin.
1. When iron-saturated hen ovotransferrin was treated with subtilisin the N-terminal half was digested at a faster rate than the C-terminal half, allowing the latter to be isolated as a single-chain fragment of mol.wt 35000. 2. In mildly acid conditions iron-ovotransferrin loses iron preferentially from its N-terminal binding site. Trypsin digestion of the resulting monoferric ovotransferrin also gave rise to a C-terminal fragment. 3. Comparison of the N-terminal fragment with the C-terminal fragments shows differences in composition, peptide 'maps', CNBr-cleavage patterns and antigenic structures. The C-terminal fragments carry the carbohydrate group of ovotransferrin. 4. Both N-terminal and C-terminal fragments donate their bound iron to rabbit reticulocytes.
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002645:Chickens; D003207:Conalbumin / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D003488:Cyanogen Bromide; D004527:Egg Proteins / Q000032:analysis*; D005260:Female; D005779:Immunodiffusion; D007501:Iron / Q000032:analysis*; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D012156:Reticulocytes / Q000378:metabolism; D013053:Spectrophotometry
D004527:Egg Proteins; D010446:Peptide Fragments; D003207:Conalbumin; D007501:Iron; D003488:Cyanogen Bromide