The proteoglycanase from human cartilage and cultured rabbit chondrocytes and its relation to osteoarthritis.

The neutral metal dependent proteoglycanase predominates as the chief neutral protease present in human patellar cartilage or released by cultured rabbit chondrocytes into the culture medium. The cultured chondrocytes released the proteoglycanase mostly in latent form. Its activation resulted in splitting off a 10,000 dalton fragment. The chondrocytes also released inhibitory activity against the proteoglycanase. Most of it was released in the first 24 hours of culture, while most of the enzyme was released in the following 48 hours. Both the human cartilage and the rabbit chondrocyte enzyme occur in two molecular weight sizes, in equilibrium with each other.