Production of recombinant bovine lactoferrin N-lobe in insect cells and its antimicrobial activity

Lactoferrin is a multifunctional, iron-binding glycoprotein found in physio logical fluids of mammals. In the present study, a gene encoding the N-term inal half (N-lobe) of bovine lactoferrin was cloned and expressed in cultur ed insect cells using a baculovirus expression system. One mutation was fou nd in the lactoferrin N-lobe gene, but it resulted in no amino acid substit ution. The recombinant lactoferrin N-lobe was secreted into the culture med ium and partially purified by means of an immobilized heparin column. The r ecombinant lactoferrin N-lobe secreted was not glycosylated, but it possess ed antimicrobial activity toward Escherichia coli O111. The recombinant pro duct synthesized and accumulated in the host cells exhibited greater electr ophoretic mobility on SDS-PAGE than the secreted product and showed no pote ncy to inhibit the growth of bacteria. It is thought that the product accum ulated intracellularly lacks antimicrobial ability due to its degradation i n the host cells or due to disruption of the active conformation. (C) 2001 Academic Press.