Fig. 2. Changes in the electrophoretic mobility of EDEN-BP is triggered by calcium. (A) Increasing amounts of CaCl₂ were added to activate CSF extract. The extracts were incubated for 3 hours, analysed on 15% Anderson SDS/PAGE gels, blotted and reacted with anti-EDEN-BP antibody. (B) Proteins extracted from nonactivated eggs (NA) and calcium ionophore-activated eggs (A) were immunoprecipitated on protein A-sepharose beads covalently coupled with anti-EDEN-BP antibodies. Extracts from nonactivated eggs were also loaded on control protein A-sepharose beads that were not in contact with the antibody (C). The bound material was analysed by electrophoresis and immunoblotted with anti EDEN-BP antibodies. a, b, b' and c indicate the different electrophoretic forms of EDEN-BP.