LACTOFERRIN BINDING TO HUMAN PLATELETS

1. Platelets bind specifically lactoferrin. 2. The lactoferrin binding to the platelets depends on the concentration of labelled lactoferrin , the number of platelets, the time of incubation and pH. 3. The bindi ng was characterized by two types of binding site: one with high affin ity and low capacity, and another with low affinity and high capacity (respectively K(aff 1) = 13.6 x 10(9) 1/mol and about 40 binding sites , and K(aff 2) = 1.23 x 10(9) 1/mol and about 135 binding sites per pl atelet). 4. Both human transferrin and bovine lactoferrin compete with human lactoferrin for the receptors. 5. The presence of lactoferrin r eceptors on the platelet membrane surface is connected most probably w ith the effect(s) on the cell function(s) of these cells.