COLLAGEN-II FROM ARTICULAR-CARTILAGE AND ANNULUS FIBROSUS - STRUCTURAL AND FUNCTIONAL IMPLICATION OF TISSUE-SPECIFIC POSTTRANSLATIONAL MODIFICATIONS OF COLLAGEN MOLECULES

Collagen II was isolated and characterized from hyaline cartilage (articular cartilage) and fibrocartilage (annulus fibrosus). Collagen II from the latter tissue has a substantially higher degree of hydroxylation and glycosylation than that isolated from articular cartilage. The higher degree of posttranslational modification was associated with a slower electrophoretic mobility, a greater resistance to mammalian collagenase digestion and a higher thermal stability. An increase of glycosylation accelerates the initial steps in fibril formation of collagen molecules but slows down the following lateral growth. The newly formed aggregates of collagen II from annulus fibrosus consisted of fibrils with a smaller diameter.