Heparin-Sepharose pattern of gelatin-adsorbed proteins. Lyophilised proteins from gelatin-agarose fraction B were resuspended in 2 ml PB and loaded on the column (1 × 13.5 cm). The unadsorbed proteins were removed by washing with PB, then 1 M NaCl in PB was used to elute the heparin-bound proteins. Four ml fractions were collected at a flow rate of 30 ml/h and pooled as indicated (fraction B1 and B2). Proteins were monitored at 280 nm.