Specific degradation of H-pylori urease by a catalytic antibody light chain
Specific degradation of H-pylori urease by a catalytic antibody light chain
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DOI：
10.1111/j.1742-4658.2005.04869.x
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发表时间：
2005-09-01
期刊：
影响因子：
5.4
通讯作者：
Uda, T
中科院分区：
文献类型：
--
作者：
Hifumi, E;Hatiuchi, K;Uda, T
长期以来，人们一直在寻找能够消化病原菌的关键蛋白质的催化抗体，以用于潜在的治疗用途。幽门螺杆菌尿素酶在人体胃的高酸性条件下对这种细菌的生存起着至关重要的作用。制备了抗H.幽门螺杆菌尿素酶识别尿素酶的α亚基，但仅轻微识别β亚基。然而，当分离时，该抗体的轻链和重链都主要与β亚基结合。HpU-9轻链（HpU-9-L）催化的裂解反应遵循Michaelis-Menten方程，Km为1.6 x 10（-5）m，k（cat）为0.11 min（-1），表明裂解反应是酶促的。在H. pylori尿素酶HpU-9-L能有效地裂解β亚基，但不能裂解α亚基，表明HpU-9-L的降解具有特异性。B-亚基中裂解的肽键为L121- A122、E124- G125、S229- A230、Y241- D242和M262- A263。BSA几乎不被HpU-9-L切割，再次表明HpU-9-L的消化是特异性的。总之，我们成功地制备了能够特异性消化H β亚基的催化性抗体轻链。幽门螺杆菌尿素酶。
Catalytic antibodies capable of digesting crucial proteins of pathogenic bacteria have long been sought for potential therapeutic use. Helicobacter pylori urease plays a crucial role for the survival of this bacterium in the highly acidic conditions of human stomach. The HpU- 9 monoclonal antibody (mAb) raised against H. pylori urease recognized the alpha-subunit of the urease, but only slightly recognized the beta-subunit. However, when isolated both the light and the heavy chains of this antibody were mostly bound to the beta-subunit. The cleavage reaction catalyzed by HpU-9 light chain (HpU-9-L) followed the Michaelis-Menten equation with a K-m of 1.6 x 10(-5) m and a k(cat) of 0.11 min(-1), suggesting that the cleavage reaction was enzymatic. In a cleavage test using H. pylori urease, HpU-9-L efficiently cleaved the beta-subunit but not the alpha-subunit, indicating that the degradation by HpU-9-L had a specificity. The cleaved peptide bonds in the b- subunit were L121- A122, E124- G125, S229- A230, Y241- D242, and M262- A263. BSA was hardly cleaved by HpU-9-L, again indicating the digestion by HpU-9-L was specific. In summary, we succeeded in the preparation of a catalytic antibody light chain capable of specifically digesting the beta-subunit of H. pylori urease.