Proteoglycans were treated for 2 h at 37°C with 10 mIU chondroitinase ABC (Sigma) in 20 µl ammonium acetate pH 8.0 or 5 mIU chondroitinase B (R&D Systems) in 20 µl 50 mM Tris-HCl pH 7.5, 50 mM NaCl, 4 mM CaCl2 or a mixture of 2 mIU each of heparinases I, II and III in 20 μl 40 mM sodium acetate, pH 7.0, and 2 mM calcium acetate (heparinases were prepared in-house, purified from E.coli, stably singularly transfected with the pET-15b vector that contained heparinase I or vector pET-19b that contained heparinase II or III, a kind gift from Jian Liu, University of North Carolina, NC).
