ISOLATION AND CHARACTERIZATION OF SHEEP LACTOFERRIN, AN INHIBITOR OF PLATELET-AGGREGATION AND COMPARISON WITH HUMAN LACTOFERRIN

Highly purified sheep lactoferrin was isolated from ovine whey in a si ngle chromatographic step (FPLC): it was characterized by electrophore sis, N-terminal sequence determination and compared with lactoferrins from other species. Sheep and human lactoferrins inhibited thrombin-in duced platelet aggregation (median inhibitory concentration: IC50 5 an d 4 mu M, respectively). Pepsin hydrolysates of human and sheep lactof errins were fractionated by reverse-phase high-performance liquid chro matography and only one peak was an inhibitor of platelet aggregation. The sheep or human lactoferrin binding to platelets was studied.