Neoepitopes reveal the features of type II collagen cleavage and the identity of a collagenase involved in the transformation of the epiphyses anlagen in development.

In long bone development, the evolution of the cartilaginous anlagen into a secondary ossification center is initiated by the formation of canals. The excavation to create the canals is achieved through lysis of the two major cartilage components, aggrecan, and the type II collagen (COL2) fibril. The present study examines the lysis of the fibril.

Protease analysis by neoepitope approach reveals the activation of MMP-9 is achieved proteolytically in a test tissue cartilage model involved in bone formation.

A principle of regulation of matrix metalloproteinase (MMP) activity has been introduced as the cysteine-switch mechanism of activation (Springman et al. 1990). According to this mechanism, a critical Cys residue found in the auto-inhibitory propeptide domain of latent proenzyme is important to determine whether or not activation is turned on or off.