Hui K S, Lajtha A
J Neurochem. 1980 Aug;35(2):489-94. doi: 10.1111/j.1471-4159.1980.tb06292.x.
Purified of prolidase from calf brain (acetone and [NH4]2SO4 fractionation) separated this enzyme from proteases, leucine aminopeptidase, master dipeptidase, and Gly-Gly dipeptidase. Prolidase was tested with peptidase and protease inhibitors, used at higher levels (35 times or more) than their ID50 for peptidases and proteases. Bacitracin, leupeptin, chymostatin, and antipain had no effect; pepstatin slightly increased activity, and only bestatin was inhibitory. Antibiotics that affect protein synthesis did not inhibit prolidase. Peptides with proline at the NH2 end activated prolidase, whereas those with proline at the carboxyl end inhibited it. Di, tri, and tetra-Pro peptides increased prolidase activity. Thyrotropin-releasing hormone had no effect on prolidase; its analog Pro-His-Pro-NH2 gave high activation and decreased the Km from 20 mM to 1.54 mM. Pro-peptide inhibitors and activators were not themselves split by prolidase. The results indicate influences of specific peptides, for both inhibition and activation, on prolidase activity.
从小牛脑中纯化出的脯氨酰二肽酶（通过丙酮和硫酸铵分级分离）将该酶与蛋白酶、亮氨酸氨肽酶、主二肽酶和甘氨酰甘氨酸二肽酶分离开来。用肽酶和蛋白酶抑制剂对脯氨酰二肽酶进行测试，其使用浓度高于它们对肽酶和蛋白酶的半数抑制浓度（ID50）35倍或更多。杆菌肽、亮抑酶肽、抑肽酶和抗蛋白酶对其没有影响；胃蛋白酶抑制剂略微增加了活性，只有氨肽酶抑制剂具有抑制作用。影响蛋白质合成的抗生素不会抑制脯氨酰二肽酶。氨基末端带有脯氨酸的肽激活脯氨酰二肽酶，而羧基末端带有脯氨酸的肽则抑制它。二肽、三肽和四肽脯氨酸增加脯氨酰二肽酶活性。促甲状腺激素释放激素对脯氨酰二肽酶没有影响；其类似物脯氨酰-组氨酰-脯氨酰胺具有高度激活作用，并将米氏常数从20 mM降至1.54 mM。前肽抑制剂和激活剂本身不会被脯氨酰二肽酶裂解。结果表明特定肽对脯氨酰二肽酶活性有抑制和激活作用。
