Nature of collagens synthesized by monkey periodontal-ligament fibroblasts in vitro.

1. First subcultures of fibroblast-like cells from adult monkey periodontal ligament were incubated in the presence of 14C-labelled amino acids and produced significant amounts of type-I and type-III collagens. 2. The proportion of type-III collagen produced was calculated on the basis of the recovery of procollagens from DEAE-cellulose chromatography to be approx. 20%, and at least 10% when analysed as collagens on CM-cellulose chromatography. 3. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the procollagens, the collagens and their CNBr peptides was used to confirm the identity of the collagen types. 4. In serum-free media extensive conversion of type-I procollagen, but not of type-III procollagen, into collagen was observed, suggesting that a specific type-I procollagen peptidase was produced. 5. The pattern of collagen synthesis was not significantly different from that obtained with fibroblasts derived from skin corium of the same animals.