Hen ovotransferrin was treated with CNBr and fractionated by gel filtration. 2. After further treatment by reduction and carboxymethylation a carbohydrate-containing fragment of molecular weight 11990 was obtained (fragment BCd). 3. The amino acid sequence of this fragment was determined. It consists of a single chain of 94 residues. 4. The structure of a tryptic glycopeptide derived from whole ovotransferrin permitted a further eight residues to be assigned at the N-terminus of fragment BCd. 5. Heterogeneity was found at two positions. 6. Further evidence has been deposited as Supplementary Publication SUP 50045 (19 pages) at the British Library (Lending Division), Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1975), 145, 5.
