To determine the activities of the five exoglycosidases that catabolize glycoconjugates (proteoglycans, glycoproteins, and glycolipids) in the synovial membrane and knee joint fluid of patients with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA).
The following exoglycosidases were analysed with the p-nitrophenyl derivatives of appropriate sugars as substrates: hexosaminidase (HEX) and its isoenzymes A and B, beta-glucuronidase, beta-galactosidase, alpha-mannosidase, and alpha-fucosidase.
Our results show that the activity of all exoglycosidases tested in the synovial membrane of patients with RA and JIA was significantly higher than in synovial fluid. We demonstrated that only the enzymatic activity of HEX was significantly higher in the tissue of patients with inflammatory diseases in comparison to the activity in the control group.
These data support the concept that the synovial cells of patients with RA and JIA are the main source of exoglycosidases, which catabolize glycoconjugates of cartilage.