Purification of the Wap65-2 from carp seminal plasma. Lines: seminal plasma (SP) hydrophobic interaction (HIC) fraction; ion exchange chromatography (IEC) fraction, and fraction eluted after preparative electrophoresis (PE). Protein samples were analyzed by PAGE (A) and SDS-PAGE (B). Proteoforms of isolated Wap65-2a and Wap65-2b after 2-DE (C). Detection of Wap65-2 in carp seminal plasma after SDS-PAGE, native PAGE, and 2-DE using anti-Wap65-2 antibodies (D). Additional file 4 indicates which part of the corresponding 2-DE of seminal plasma is presented on the blot (D).