COLLAGENASE - A KEY ENZYME IN COLLAGEN TURNOVER

The primary agents responsible for cartilage and bone destruction in j oint diseases are active proteinases that degrade collagen and proteog lycan. All four main classes of proteolytic enzymes are involved in ei ther the normal turnover of connective tissue or its pathological dest ruction. These proteinases are made by different cells found within th e joints. Both extracellular and intracellular pathways exist and indi vidual enzymes can be inhibited by specific proteinaceous inhibitors t hat block their activity. Recent research has implicated the matrix me talloproteinases (MMPs) in many of the processes involved in joint dis eases. The metalloproteinases are capable of degrading all components of the extracellular matrix. This family of proteinases contains a gro up of at least three collagenases that are capable of degrading native fibrillar collagen. Collagen degradation within joint disease is reco gnized as the irreversible step in the destruction of cartilage that l eads to a failure in joint function. The collagenases are the enzymes necessary to initiate collagen turnover in normal connective tissue tu rnover and in disease.