m-Calpain in rat growth plate chondrocyte cultures: its involvement in the matrix mineralization process

Mineralization of cartilage is a key step in the development and growth of bone. A mineralization experiment conducted with rates reveals that the enzyme m-Calpain, a Ca2+ -dependent neutral cysteine proteinase, controls the mineralization of cartilages by degrading proteoglycan during development of the cells. The amount of m-Calpain and its activity in pelleted cultures of rat growth plate chondrocytes increases as the chondrocytes differentiate into the hypertrophic cells and mineralization takes place. In the presence of m-Calpain inhibitors matrix mineralization is suppressed.