Study on prolidase dificiency-in special reference to proline metabolism

本文测定了氨脯氨酸二肽酶缺乏姐妹篇（症状（+）、症状（-））和两名正常人培养的皮肤成纤维细胞的氨脯氨酸二肽酶和脯氨酸酶活性。结果I.对Gly-Pro、Leu-Pro、Val-Pro的氨酰基脯氨酸二肽酶活性在两个患者中降低至正常酶活性的约3%。然而，在这些氨脯氨酸酶缺乏的患者中，针对Met-Pro、Ala-Pro、Phe-Pro的氨脯氨酸酶活性明显存在。2.在不同浓度的锰（ImM，IOOmM，IM）下，正常受试者的氨酰基脯氨酸二肽酶对Gly-Pro的活性在IOOmM锰下最高。然而，患者的酶活性在ImM时最高。3.测定了氨酰基脯氨酸二肽酶对Met-Pro的热稳定性。患者的酶似乎比对照组略不稳定。4. 0.05mM对氯汞苯甲酸可抑制病人和正常人的氨酰基脯氨酸二肽酶活性。然而，预孵育的酶溶液与ImM锰似乎保护只有正常的酶被抑制。5.当酶溶液与Gly-Pro预孵育时，氨酰基脯氨酸二肽酶对Met-Pro的活性似乎仅在患者中被抑制。置评.在脯氨酰二肽酶缺乏症，对一些底物，如Gly-Pro的酶活性几乎不存在，但对其他亚氨基二肽与C-末端脯氨酸的活动是相当存在的。我们认为，上述结果表明，酶蛋白不是不存在，但改变了氨酰基脯氨酸二肽酶缺乏症。症状（-）姐妹的脯氨酸酶活性略高，但变化不明显。

Prolidase and prolinase activities of cultured skin fibroblasts obtained from prolidase deficient sisters(symptom(+),symptom(-)) and two normal subjects were assayed. Results. I. prolidase activities against Gly-Pro, Leu-Pro, Val-Pro were decreased to about 3% of normal enzyme activities in both patients. However, prolidase activities against Met-Pro, Ala-Pro, Phe-Pro were notably present in these prolidase deficient patients. 2. With different concentrations of manganese (ImM, IOOmM, I M), prolidase activities against Gly-Pro of the normal subjects were highest with IOOmM manganese. However, the enzyme activities of the patients were highest with ImM. 3. The heat stability of prolidase against Met-Pro was assayed. The enzyme of the patients seemed to be slightly less stable than the controls. 4. The prolidase activies in both patients and normal subjects were suppressed with 0.05mM p-chloromercuribenzoic acids. However, preincubation of the enzyme solution with ImM manganese seemed to protect only the normal enzymes from being inhibited. 5. When the enzyme solution was preincubated with Gly-Pro, the prolidase activities against Met-Pro seemed to be inhibited only in the patients. Comment. In the prolidase deficiency, the enzyme activities against some substrates such as Gly-Pro were almost absent but the activities against other iminodipeptides with C-terminal proline were considerably present. We supposed that the results described above suggested that the enzyme proteins were not absent but were altered in prolidase deficiency. No remarkable changes of prolinase activities were found in spite of slightly higher activities in symptom(-) sister.