AnVWF specific-activity is reciprocal to ancestral FVIII. (A) Activities of AnVWF molecules were determined by VWF:GPIbM (red bars) and VWF:RCo (blue bars) and normalized to antigen levels to generate specific-activities. VWF:RCo data are presented as the mean of 2 purified AnVWF lots. Specific-activities of VWF (open squares) and FVIII (closed circles) from the primate (B) and rodent (C) lineages were plotted in relation to their predicted age of ancestry (million years ago [mya]) as determined by TimeTree. Specific-activities of ancestral FVIII were determined by one-stage coagulation activity normalized to absorbance after extinction coefficient correction. Specific-activities of orthologous FVIII protein was determined previously.^5,12