Degradation of fibrillar collagens by matrix metalloproteinases (MMPs) is thought to be a major catabolic pathway in various connective tissues. However, the complex structure of collagen molecules and their degradation products makes specific assay of these events very challenging. In this chapter, those particular features of collagen biochemistry which contribute to the difficulty of measuring its degradation will be outlined and the principles of recently developed methodology for assaying collagen degradationin situwill be described. Although the most abundant collagen in the body is type I collagen (found, for example, in skin, bone, ligaments and tendons), much of this chapter will focus on type II collagen, the major collagen of hyaline cartilage, for which much of the new methodology has already been established.
