Separation and Characterization of the C-Terminal Half Molecule of Bovine Lactoferrin

Abstract

The C-terminal half molecule (C lobe) of bovine lactoferrin was isolated by mild tryptic hydrolysis of lactoferrin followed by gel filtration and ionexchange chromatography. The identity of the fragment was established by determining its N-terminal and C-terminal amino acid sequences and comparing them with the amino acid sequence of intact lactoferrin. The isoelectric point of the C lobe ranged between pH 6.2 and 6.5 as measured by isoelectric focusing on polyacrylamide gels. The circular dichroic spectrum in the range of 250 to 350 nm of the C lobe differed slightly from that of intact lactoferrin. The pattern of lectin reactivity was similar for both the C lobe and intact lactoferrin. The C lobe showed partial antigenic identity with intact lactoferrin as demonstrated by the double immunodiffusion method, and pH dependence of iron binding of C lobe is the same as that of intact lactoferrin molecule. © 1993, American Dairy Science Association. All rights reserved.