Characterization of the protein and glycan moieties in different forms of bovine lactoferrin

The BrCN cleavage of lactoferrin-a or -b (LF-a or LF-b) led to the observation of four fragments by SDS-PAGE, whose molecular masses were 77, 58, 52, and 30 kDas, or 74, 54, 47, and 30 kDas, respectively. N-Terminal amino acid sequence analyses show that the sequences of 58, 52, and 30 kDa fragments (residues 64-471, 130-471, and 472-689) of LF-a coincide with those of the 54, 47, and 30 kDa fragments of LF-b. respectively. All these fragments, which were positive by PAS staining, were not stained after being treated with glycopeptidase F. This treatment changed the 58 and 52 kDa fragments of LF-a to the 54 and 47 kDa fragments, respectively, whose molecular masses were the same as those of the treated fragments of LF-b. The 58 and 52 kDa fragments of LF-a bound to the lectin, Ricinus communis agglutinin, while the 54 and 47 kDa fragments of LF-b hardly bound to it.