Rates of protein turnover at specific sites of the rat incisor periodontal ligament.

Extraction of rat incisor periodontal ligament using neutral salt solutions was carried out on a site-specific basis following administration of 3H-labelled proline, the incorporation of 3H-proline into soluble proteins of different molecular weights was determined by SDS electrophoresis and scintillation counting. Tracer was incorporated primarily into 3 fractions with Mr = greater than 120K, 100K and 45-65K. Appearance of 3H-proline in low molecular weight components which cross-reacted with antibodies to Type 1 collagen (presumably collagen breakdown products) within 30 minutes of administration suggests a pool of collagen which is rapidly turning over. The rate of maturation of collagen from this soluble to insoluble forms may represent a level of post-translational control within the tissue which may be directly related to tissue morphostasis.