Normal hydroxylation of proline in collagen synthesized by skin fibroblasts from a patient with prolidase deficiency.

The extent of hydroxylation of proline in collagen synthesized and secreted into the culture medium by skin fibroblasts derived from a patient with prolidase deficiency has been examined and found to be normal. It would seem likely that to a considerable extent the urinary proline-containing dipeptides apparent in this condition are derived from sources other than collagen.