Lactoferrin (LF) is an iron-binding glycoprotein of the innate host defence system. To elucidate the role ofN-linked glycosylation in protection of LF against proteolysis, we compared the tryptic susceptibility of human LF (hLF) variants from human milk, expressed in human 293(S) cells or in the milk of transgenic mice and cows. The analysis revealed that recombinant hLF (rhLF) with mutations Ile130fiThr and Gly404fiCys was about twofold more susceptible than glycosylated and unglycosylated variants with the naturally occurring Ile130 and Gly404
