Fig. 7.

SDS-PAGE and immunoblotting of link protein from different individuals. Proteins from guanidine extracts of OA articular cartilage were analyzed by electrophoresis on polyacrylamide gels, and the fractionated proteins then transferred to nitrocellulose membranes. The membrane was analyzed by immunoblotting using an antibody recognizing link protein (αLP). Cartilage samples were obtained adjacent to the lesion (L5 and L30). midway between the lesion and the joint margin (M5 and M30), and remote from the lesion (R5 and R30) from the femoral condyles and are shown for two representative individuals. Molecular weights of reference proteins are indicated at the left hand side of the blot. Schematic diagrams depicting the structure of link protein components of different sizes are included at the right side of the blot. LP1 and LP2 represent the intact link protein, whereas LP3 and LP frag represent proteolytic cleavage products