Urine glycyl-L-proline increase and skin trophicity
Glycyl-L-proline (gly-pro) is an end product of collagen metabolism that is further cleaved by prolidase (EC 184.108.40.206); the resulting proline molecules are recycled into collagen or other proteins. We postulated a relationship between defective gly-pro hydrolysis, increased collagen degradation and skin destruction. This relationship was tested using HPLC to measure the gly-pro in urine. 24 hour urine samples were collected from 27 old people (86 ± 6 years old), of whom 15 were suffering from skin pressure sores of the sacrum or calcaneus. The urine from patients with pressure sores contained significantly more gly-pro than the urine from the control. A cut-off at 7μmol/ mmol creatinine gave the test a positive predictive value of 70%. Collagen breakdown was also increased as indicated by the increase of hydroxyproline (hyp) in the urine. But this breakdown seemed to stop at the gly-pro step.
KeywordsAmino acids Glycyl-L-proline Urine Trophicity Collagen
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