Further Evidence for the Accumulation of a Hydroxyproline-deficient, Collagenase-degradable Protein during Collagen Biosynthesis in Vitro

By use of purified bacterial collagenase it has been possible to demonstrate that a proline-rich, hydroxyproline-deficient, collagenase-degradable protein accumulates in many collagen-forming systems when proline hydroxylation is impaired. These experiments provide further evidence that proline is incorporated into a collagen-like polypeptide prior to hydroxylation. The collagenase-tannic acid procedure may be used as a means of studying collagen synthesis independent of proline hydroxylation.