Collagen polypeptides: normal release from polysomes in the absence of proline hydroxylation.

It is not necessary that proline be hydroxylated for the completion and release of nascent collagen chains from polysomes. Hydroxylation of collagen proline in vivo normally takes place predominantly on nascent polypeptides; however, in the presence of an inhibitor of hydroxylation, unhydroxylated chains are released. These chains may subsequently be hydroxylated when the inhibition is removed. The results clarify a controversy over the site of proline hydroxylation.