Studies on Prolidase Deficiency - Effect of Iminodipeptides on Collagen Metabolism

1)采用生物化学方法检测了增殖酶缺陷姐妹、具有典型临床表现的老年人和轻度临床表现的年轻人皮肤成纤维细胞的增殖酶（PD）活性。2)采用DESE-5PW柱高效液相色谱法分离培养的人皮肤成纤维细胞中增殖酶同工酶（PD-I，II）。3)研究大鼠皮肤创面愈合过程中PD的活性。4)测定新生小鼠表皮提取物的PD活性。结果1)除Gly-Pro外，两姐妹均有不同程度的PD活性。在二价阳离子的影响和底物特异性方面，症状（+）患者和症状（-）姊妹患者的PD活性没有可检测到的差异。2)对照中，PD-1对Gly-Pro、Ala-Pro、Met-Pro的活性依次递减。而PD-II对Met- More Pro、Gly-Pro、Ala-Pro的活性依次递减。在增殖酶缺陷姐妹中，PD-I活性未检测到，而PD-II活性存在。症状（+）患者和症状（-）姊妹患者的PD-II底物特异性无显著差异。3)创面附近皮肤PD活性在第1天下降，第14天逐渐升高，约为对照组的3倍。4)在新生小鼠表皮中检测PD活性。Mn^<2+>具有有效的激活作用。1)在这项研究中，我们估计了来自症状（+）患者，她的症状（-）姐妹和对照组的培养皮肤成纤维细胞的PD活性。两名患者在粗纤维原纤维提取物中对Gly-Pro以外的底物均有一定程度的PD活性。这说明PD不是缺失而是改变了。2)最近，从人体细胞和各种组织中分离出两种形式的PD。在我们的患者中，两姐妹的PD-I活性都无法确定，而PD-II活性存在。使用部分纯化的PD-II对底物特异性的研究显示，症状（+）患者和症状（-）姐妹之间存在差异。3)伤后14 d，伤口附近PD活性升高。局部供应由PD活性增加产生的氨基酸可能在一定程度上弥补了伤口愈合中用于合成新胶原蛋白的氨基酸。PD功能障碍与伤口愈合的关系尚不清楚。然而，内源性游离脯氨酸循环不足可能导致伤口愈合延迟。4)表皮中PD活性的存在提示PD可能参与了上皮化。在这些背景下，亚氨基二肽对胶原代谢的影响将被研究。少

1) The prolidase(PD) activities of cultured skin fibroblasts derived from prolidase deficient sisters, the elder with typical clinical manifestations and the younger with only slight clinical manifestations were examined biochemically. 2) Isozymes of prolidase(PD-I,II) from cultured human skin fibroblasts were separated by DESE-5PW column HPLC. 3) PD activities in rat skin during wound healing were studied. 4) PD activities in an extract of newborn mouse epidermis were examined. Results 1) PD activities against several substrates other than Gly-Pro were present to some degree in both sisters. There were no detectable differences in PD activity between symptom(+) patients and the symptom(-) sister with respect to the effect of divalent cations and the substrate specificity. 2) In control, activities of PD-1 were decreased in the descending order of activities against Gly-Pro, Ala-Pro, Met-Pro. However, activities of PD-II were decreased in the descending order of activities against Met- … More Pro, Gly-Pro, Ala-Pro. In prolidase deficient sisters, the activities of PD-I could not be detected, while the activities of PD-II were present. No remarkable differences were seen between the substrate specificities of the PD-II from symptom(+) patient and symptom(-) sister. 3) PD activities in rat skin adjacent to the wound were decreased at day 1 and gradually increased to about three times those of controls at day 14. 4) PD activities were detected in newdorn mouse epidermis. Mn^<2+> had a potent activating effect. Discussion 1) In this study, we estimated PD activity in cultured skin fibroblasts derived from a symptom(+) patient, her symptom(-) sister and controls. PD activities against substrates other than Gly-Pro were present to some degree in both patients in crude fibroblas extract. This indicates that PD was not absent but altered. 2) Recently, two forms of PD have been separated from human cells and various tissues. In our patients, activity of PD-I could not be determined in both sisters,while activity of PD-II present. The studies of substrate specificity using partially purified PD-II showed on differences between symptom(+) patient and symptom(-) sister. 3) The activities of PD adjacent to the wound were elevated at 14 days after injury. The local supply of amino acids produced by increased PD activity may compensate to some extent for amino acids used for synthesis of new collagen in wound healing. The relation of the dysfunction of the PD to the pathogenesis of the wound healing is unclear. However, insufficient recycling of endogenous free proline might cause delay in wound healing. 4) The existence of PD activities in the epidermis may suggest a possible involvement of PD in epitheilialization. In these contexts effect of iminodipeptides on collagen metabolism will be investigated. Less