Isolation and purification of soybean core histone from leaves with RP-HPLC and FPLC. A: Strategies used in this experiment. B: Spectrum of histone isolation with RP-HPLC. The core histones were extracted in acid and separated by RP-HPLC. They were eluted in the sequence of histone H2B, H4, H2A and H3, while histone H1 was not isolated. Several variants of histone H2B, H2A and H3 were separated and their retention times were labeled on the top of their corresponding peaks.