Schweisfurth H, Reinhart E, Heinrich J, Brugger E
J Clin Chem Clin Biochem. 1983 Oct;21(10):605-9. doi: 10.1515/cclm.1983.21.10.605.
Kininase I (carboxypeptidase N; EC 3.4.17.3) consists of carboxypeptidase N1 (CN1) and carboxypeptidase N2 (CN2); these two enzymes can be differentiated by their activities towards hippuryl-L-arginine and hippuryl-L-lysine, respectively. A spectrophotometric assay for both carboxypeptidases in human serum is described and the biochemical behaviour of these enzymes investigated. The pH optima are found to be 8.4 for CN1 and CN2. The Michaelis-Menten constants are: CN1 4.59 +/- 0.03 mmol/l; CN2 37.26 +/- 3.49 mmol/l. CN2 can be inhibited by EDTA (76%), dimercaprolum (97%) and phenanthroline (98%). Diisopropylfluorophosphate has no influence on both enzymes. Elevated haemoglobin only interferes with CN1 measurements, and high bilirubin concentrations slightly alter the activity of both enzymes. High CN1 activities were found in sera of patients with sarcoidosis, and elevated CN2 activities were found in lung cancer.
激肽酶I（羧肽酶N；EC 3.4.17.3）由羧肽酶N1（CN1）和羧肽酶N2（CN2）组成；这两种酶可分别通过它们对马尿酸-L-精氨酸和马尿酸-L-赖氨酸的活性来区分。本文描述了一种用于检测人血清中这两种羧肽酶的分光光度法，并对这些酶的生化行为进行了研究。发现CN1和CN2的最适pH值均为8.4。米氏常数分别为：CN1 4.59±0.03 mmol/L；CN2 37.26±3.49 mmol/L。CN2可被EDTA（76%）、二巯丙醇（97%）和邻菲罗啉（98%）抑制。二异丙基氟磷酸酯对这两种酶均无影响。血红蛋白升高仅干扰CN1的测量，高胆红素浓度会轻微改变这两种酶的活性。结节病患者血清中发现CN1活性升高，肺癌患者中发现CN2活性升高。
