The effect of NoC-1 on the collagen binding of VWF is independent of calcium ions.

(A) VWF (8 nM) was incubated with 0.8 to 80 nM E3CaG-1 or 0.008 to 800 nM NoC-1. Aliquots of the reactions were analyzed for the average VWF multimer size (■) and for the generation of new thiols in VWF (▪). The dotted lines represent no change in VWF multimer size (top line) or thiols in VWF (bottom line). The asterisks indicate significant difference compared to control (P < .05). The small increase in MPB labeling (▪) at high concentrations of NoC-1 was not significantly different compared to control (P > .05). (B) VWF (8 nM) was incubated with TSP-1 or the NoC-1 fragment (80 nM) in the absence or presence of EDTA (10 mM). Aliquots of the reactions were analyzed for the collagen-binding affinity and VWF antigen level. The asterisks indicate significant difference compared to control (P < .05).