ELISA detection of endogenous vWF. Platelets from ashen homozygous (ash/ash) and heterozygous mice controls (+/ash) (a) and from gunmetal homozygous (gm/gm) and heterozygous mice controls (+/gm) (b) were lysed and the indicated amount of total protein incubated with 100 μl of buffer in a sandwich ELISA (see Methods). Each step corresponds to a 1:2 dilution, and duplicates were made for each point. The results are representative of three independent experiments. The OD450nm value from the blank reaction (buffer only) was subtracted.