Kinetic analyses of the binding of leukemia inhibitory factor to receptors on cells and membranes and in detergent solution

Abstract

The equilibrium and kinetic properties of leukemia inhibitory factor (LIF) binding to a range of cell types have been compared. When binding was examined at 4 °C, the majority of cells were found to express a single class of high affinity LIF receptor (KD = 20-100 pM; ka = 2-8 × 108 min-1 M-1; kd = 0.0004-0.0011 min-1). In contrast, certain activated macrophage populations expressed apparently independent classes of high and low affinity LIF receptor. The low affinity receptors differed from the high affinity receptors in terms of the dissociation rate of the receptor-ligand complex (KD = 1-2 nM; Ka, = 3-7 × 108 min-1 M-1; kd = 0.30-0.67 min-1). At 37 °C, the interaction of LIF with its high..