NORMAL PRODUCTION, NATURE, AND EXTENT OF INTRACELLULAR DEGRADATION OFNEWLY SYNTHESIZED COLLAGEN IN FIBROBLASTS FROM A PATIENT WITH PROLIDASE DEFICIENCY

We have examined the extent of intracellular degradation of newly synt hesized collagen occurring in fibroblasts from a patient with prolidas e deficiency, a rare, autosomal recessively inherited disorder, in whi ch a lack of prolidase, which normally cleaves imidodipeptides with a C-terminal Pro or Hyp residue, results in hyperimidodipeptiduria. The main clinical feature of the condition is chronic, intractable ulcerat ion of the skin, and the suggestion has been made that it represents a specific disorder of collagen metabolism. Although most of the hydrox y-[(14)]proline derived from the intracellular degradation of newly sy nthesized collagen in prolidase-deficient fibroblasts occurred in imid odipeptides, with a similar chromatographic profile to those occurring in the patient's urine, the proportion of collagen undergoing such de gradation was as in control cells. No abnormality was found in other p arameters of collagen metabolism studied, and the results confirm that , although the pathogenesis of its clinical manifestations remains unc lear, the disorder is one of protein degradation in general