N. Buist, J. Strandholm, J. F. Bellinger
Dec 1, 1972
Citations
1
Influential Citations
53
Citations
Quality indicators
Journal
Metabolism: clinical and experimental
Abstract
Abstract Some studies have been performed upon a urine sample obtained from a patient previously reported by Goodman et al. to exhibit massive iminodipeptiduria. 31,000 μmole (3.34 g) of dipeptide proline and 1900 μmole (250 mg) of dipeptide hydroxyproline were excreted in 24 hr. In addition to the six dipeptides originally reported, we have isolated and quantitated Pro-Pro (2180), Ala-Pro (1360), Tyr-Pro (1040), Phe-Pro (1880), and Lys-Pro (140). Twenty-four-hr values in micromoles are given in parentheses. Enzymatic data suggest the existence also of Asp-Pro (1610), Glu-Pro (70), Thr-Pro (1680), Ser-Pro (1630), His-Pro (390), Arg-Pro (100), and Tyr-Pro (170). No hydroxyproline-containing dipeptides have been isolated, but chromatographic evidence suggests the presence of Ser-Hyp, Glu-Hyp, Gly-Hyp, Ala-Hyp, Pro-Hyp, (or Hyp-Pro). All the abnormal peptides were hydrolyzed by a preparation of prolidase in vitro. The data suggest that a generalized defect of imino-carboxyterminal dipeptide catabolism was present, and they are consistent with the possibility that the patient possessed a defect of tissue prolidase activity. From the data, it can be calculated that 2.0–2.5 g of collagen was being degraded per day.