Figure 3: SAP conformation during amyloid precursor protein binding. (A) Effect of different doses of HSA, in the presence of 2 mM Ca2+, on SAP binding to HSA or AP-HSA was assessed by ELISA. Error bars are means ± SEM of duplicate wells (*p<0.05 compared with HSA). Similar results were obtained from at least two independent experiments. (B, C) Biotinylated SAP was incubated in the presence or absence of Ca2+ (B) or 80 mg/ml HSA plus Ca2+ (C), and the molecular weight of SAP was assessed by gel filtration. Fractions were collected and analysed by ELISA.