title: Prolyl hydroxylase production can be uncoupled from the regulation of procollagen synthesis.
abstract: Primary avian tendon (PAT) cells increase the production of procollagen from 10-12% to 40-50% of total protein synthesis in response to the addition of ascorbate and an increasing cell density. We now show that prolyl hydroxylase (PH) also increases its activity by greater than five-fold in response to increasing cell density; but unlike procollagen production, this is independent of the presence of ascorbate. The increased activity is a result of greater enzyme production and not a shift in the ratio of inactive to active forms which remains constant at about 10% of the total enzyme proteins. We present the possibility that at low cell density the levels of PH activity could limit production of collagen.
authors.forename: W W
authors.initials: WW
authors.lastname: Kao
authors.forename: C W
authors.initials: CW
authors.lastname: Kao
authors.forename: R I
authors.initials: RI
authors.lastname: Schwarz
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002452:Cell Count; D002478:Cells, Cultured; D002642:Chick Embryo; D007123:Immunoelectrophoresis, Two-Dimensional; D007700:Kinetics; D011347:Procollagen / Q000096:biosynthesis*; D011393:Procollagen-Proline Dioxygenase / Q000096:biosynthesis*; D013710:Tendons
chemical_list: D011347:Procollagen; D011393:Procollagen-Proline Dioxygenase; D001205:Ascorbic Acid