Type II collagen from lathyritic rat chondrosarcoma: preparation and in vitro fibril formation.

Intact type II collagen monomer was isolated in 10-20% yield from lathyritic rat chondrosarcoma and purified to homogeneity. On warming in neutral solution, the collagen formed a mixture of D-periodic native fibrils and thin filaments with no apparent structure. There were characteristic lag and growth phases in the turbidity profile. cooling dispersed or dissolved the fibrils leaving thin filaments. The fibrils were very wide, up to 2.0 micrometers compared to the 10 to 40 nm fibrils present in situ. They had the appearance of stiff tactoids compared to the very long and flexible fibrils obtained from type I collagen under similar conditions. Type II collagen also required higher temperatures and concentrations than type I to form fibrils. The continued presence of thin filaments when type II fibril formation was complete suggests either that filaments are in slow equilibrium with fibrils or that they may not be intermediates but rather a separate product.