Figure 6. Western blot images of aliquots of the commercially sourced ‘decorin’ and ‘biglycan’ and purified human aggrecan following separation on 4–12% Bis-Tris gels.

The PGs in (A)–(C) had been digested with chondroitinase ABC, keratanase and keratanase II (removing CS, DS and KS GAG chains). Lanes 1 and 3 of (A)–(C) contain different batches of ‘decorin’, lane 4 contains ‘biglycan’ and lane 2 contains the molecular weight standards. The expected molecular weight of the intact core protein of both biglycan and decorin is approximately 45 kDa (*). The membranes were probed with antibodies to (A) biglycan (PR-85); (B) decorin (DS-1) and (C) aggrecan (6B4). For the membranes in (D)–(F), lane 1 contains the molecular weight standards; lanes 2 and 3 contain ‘biglycan’ without and with prior enzymatic digestion with chondroitinase ABC respectively and in lane 4 is purified human aggrecan without prior digestion. These membranes were probed with (D) fibromodulin; (E) 1B4, which detects less-sulfated KS and (F) lumican.