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Publication history
16 Aug 2005
(Received 29 April 2005, revised 7 July 2005, accepted 18 July 2005)
FEBS Journal
Volume 272 Issue 17 Page 4497-4505, September 2005
To cite this article: Emi Hifumi, Kenji Hatiuchi, Takuro
Okuda, Akira Nishizono, Yoshiko Okamura, Taizo Uda (2005)
Specific
degradation of H. pylori urease by a catalytic antibody light chain
FEBS Journal 272 (17), 4497–4505.
doi:10.1111/j.1742-4658.2005.04869.x
Specific degradation of H. pylori urease by a catalytic antibody light chain
- Emi Hifumi1,21 Prefectural University of Hiroshima, Faculty of Bioscience and Environment, Hiroshima, Japan2 CREST of JST (Japan Science and Technology Corporation), Saitama, Japan,
- Kenji Hatiuchi22 CREST of JST (Japan Science and Technology Corporation), Saitama, Japan,
- Takuro Okuda22 CREST of JST (Japan Science and Technology Corporation), Saitama, Japan,
- Akira Nishizono33 Oita University, Faculty of Medicine, Oita, Japan,
- Yoshiko Okamura1,21 Prefectural University of Hiroshima, Faculty of Bioscience and Environment, Hiroshima, Japan2 CREST of JST (Japan Science and Technology Corporation), Saitama, Japan and
- Taizo Uda1,21 Prefectural University of Hiroshima, Faculty of Bioscience and Environment, Hiroshima, Japan2 CREST of JST (Japan Science and Technology Corporation), Saitama, Japan
Fax: +81 824 74 0191
Tel: +81 824 74 1756
E-mail: uda@pu-hiroshima.ac.jpHpU-9-H, HpU-9 heavy chain; HpU-9-L, HpU-9 light chain; VIP, vasoactive intestinal peptide.
Abstract
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
α-subunit of the urease, but only slightly recognized the β-subunit. However,
when isolated both the light and the heavy chains of this antibody were mostly
bound to the β-subunit. The cleavage reaction catalyzed by HpU-9 light chain
(HpU-9-L) followed the Michaelis-Menten equation with a Km of
1.6 × 10
5 m and a
kcat of 0.11 min1, suggesting that the cleavage
reaction was enzymatic. In a cleavage test using H. pylori urease,
HpU-9-L efficiently cleaved the β-subunit but not the α-subunit, indicating that
the degradation by HpU-9-L had a specificity. The cleaved peptide bonds in the
β-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 β-subunit of
H. pylori urease.
