Collagenase-like (CL) peptidase activity in synovial fluid from patients with rheumatoid arthritis

We found the presence of collagenase-like (CL) peptidase in synovial fluid by a highly sensitive fluorescence assay using (succinyl-Gly-Pro-Leu-Gly-Pro)-4-methyl-coumaryl-7-amide (Suc-GPLGP-MCA) as a substrate. Suc-GPLGP-MCA is hydrolyzed at the Leu-Gly bond by CL-peptidase. The CL-peptidase activity in synovial fluid was significantly higher in patients with rheumatoid arthritis (RA) than in patients with osteoarthritis (OA) and in arthropathy-free controls. No significant difference in CL-peptidase activity in synovial fluid was found between patients with OA and arthropathy-free controls.