Fig. 4.

Analysis of GAG substitution pattern on intervertebral disc aggrecan. Proteoglycan A1-preparation from a 24 year old was treated with trypsin and then analyzed by agarose gel electrophoresis. Proteoglycan fragments possessing the aggrecan CS1 domain or KS chains were identified by immunoblotting. They were analyzed directly (1) or following treatment with chondroitinase ABC (2) or keratanase II (3) to determine GAG substitution. Proteoglycans from the annulus fibrosus (AF) and nucleus pulposus (NP) were analyzed separately