Hydrolysis of human haemoglobin by Ov-CB-1 and Ov-CF-1 and analysis of digests by nanoLC-ESI-MS/MS. (A) Purified human haemoglobin (Hb) was digested by Ov-CB-1 and Ov-CF-1 in 0.1 M sodium acetate buffer (pH 4.0), containing 1 mM DTT and 1mM EDTA at 37°C. Reactions were stopped at time 0 and at various time-points (10, 15, 30, 60, 90, 120, 240 and 360 min) by the addition of the cysteine protease inhibitor E-64 and aliquots analysed on 4-12 % Bis-Tris NuPage gels. (B) Map of Hb α- and β-chains indicating sites of Ov-CB-1 and Ov-CF-1 cleavage. Cleavage sites within Hb present in 15 min reactions as determined by nanoLC-ESI-MS/MS are shown. Arrows, cleavage sites shared by Ov-CB-1 and Ov-CF-1; open arrowheads, Ov-CB-1-specific cleavage sites; filled arrowheads, Ov-CF-1-specific cleavage sites. (C) Frequency of peptides of varying length released following hydrolysis of Hb alpha and beta chains by Ov-CB-1 and Ov-CF-1.