Fig 1: Ion-exchange chromatography of trypsin autolyzate. The depicted separation was performed on a Uno S12 column (15 × 68 mm; Bio-Rad, Hercules, CA, USA) using a linear gradient of NaCl (0–1 M) in 100 mM Tris-HCl, pH 7.1, containing 10 mM CaCl2. The gray box indicates a time window, in which the respective ?-trypsin fraction was collected. The black line shows absorbance at 280 nm, the red line refers to conductivity of the eluate.