食品科学

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牛胰脏组织蛋白酶L的纯化和酶学性质

崔昱清1,2,王复龙1,2,崔保威1,2,郭秀云1,2,李君珂1,2,刘世欣1,2,刘森轩1,2,彭增起1,2,*   

  1. 1.南京农业大学食品科技学院,江苏 南京 210095;2.食品安全与营养协同创新中心,江苏 南京 210095
  • 出版日期:2015-08-15 发布日期:2015-08-17

Purification and Characterization of Cathepsin L from Bovine Pancreas

CUI Yuqing1,2, WANG Fulong1,2, CUI Baowei1,2, GUO Xiuyun1,2, LI Junke1,2, LIU Shixin1,2, LIU Senxuan1,2, PENG Zengqi1,2,*   

  1. 1. College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China;
    2. Synergetic Innovation Center of Food Safety and Nutrition, Nanjing 210095, China
  • Online:2015-08-15 Published:2015-08-17

摘要:

新鲜牛胰脏匀浆物经酸化粗提后,再通过盐析、柱层析等步骤纯化,制备了0.58 mg纯酶,纯化倍数达530.54。经凝胶电泳分析,该酶有2 个亚基,分子质量为29.1 kD和18.9 kD。牛胰脏组织蛋白酶L的最适反应温度为50 ℃,最适反应pH值为6.5。巯基还原剂二硫苏糖醇、L-半胱氨酸均明显激活了该酶活性,10 μmol/L的N-(反式-环氧丁二酰基)-L-亮氨酸-4-胍基丁基酰胺(E-64)可完全抑制其活性。1 mmol/L的Zn2+对酶活性有明显抑制作用。该纯化酶可水解苄氧羰基-苯丙氨酰-精氨酰-甲基香豆素(Z-Phe-Arg-MCA),其Km值为3.52 μmol/L。

关键词: 组织蛋白酶L, 牛胰脏, 纯化, 酶学特性

Abstract:

In this study, 0.58 mg of purified enzyme was prepared from acidification and subsequent extraction of fresh
bovine pancreas homogenate followed by purification through salting out and column chromatography. The purification
fold was 530.54. The purified enzyme had two subunits with molecular weights of 18.9 and 29.1 kD, respectively on SDSpolyacrylamide
gel electrophoresis (SDS-PAGE). The optimum reaction temperature for bovine pancreas cathepsin L was
50 ℃, and the optimum pH was 6.5. Its enzyme activity was efficiently activated by dithiothreitol (DTT) and L-cysteine
(L-Cys), while it could be completely inhibited by 10 μmol/L E-64 and evidently suppressed by 1 mmol/L Zn2+. The purified
enzyme could hydrolyze Z-Phe-Arg-MCA with a Km value of 3.52 μmol/L.

Key words: cathepsin L, bovine pancreas, purification, enzymatic characterization

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