Isopeptidase activity of human transglutaminase 2:disconnection from transamidation and characterization by kinetic parameters


Transglutaminase 2 (TG2) is a multifunctional protein with diverse catalytic activities and biological roles. Its best studied function is the Ca2+-dependent transamidase activity leading to formation of γ-glutamyl-ε-lysine isopeptide crosslinks between proteins or γ-glutamyl-amine derivatives. TG2 has a poorly studied isopeptidase activity cleaving these bonds. We have developed and characterised TG2 mutants which are significantly deficient in transamidase activity while have normal or increased isopeptidase activity (W332F) and vice versa (W278F). The W332F mutation led to significant changes of both the Km and the Vmax kinetic parameters of the isopeptidase reaction of TG2 while its calcium and GTP sensitivity was similar to the wild type enzyme. The W278F mutation resulted in six times elevated amine incorporating transamidase activity demonstrating the regulatory significance of W278 and W332 in TG2 and that mutations can change opposed activities located at the same active site. The further application of our results in cellular systems may help to understand TG2 -driven physiological and pathological processes better and lead to novel therapeutic approaches where an increased amount of cross-linked proteins correlates with the manifestation of degenerative disorders.

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Divisions: College of Health & Life Sciences > School of Biosciences
College of Health & Life Sciences > Chronic and Communicable Conditions
College of Health & Life Sciences
College of Health & Life Sciences > School of Biosciences > Cellular and Molecular Biomedicine
College of Health & Life Sciences > School of Biosciences > Cell & Tissue Biomedical Research
Additional Information: The final publication is available at Springer via
Uncontrolled Keywords: human transglutaminase 2,isopeptidase activity,γ-glutamyl-hydrolase,transamidation,regulation of activities,moonlighting enzyme,Biochemistry,Clinical Biochemistry,Organic Chemistry
Publication ISSN: 1438-2199
Last Modified: 19 Apr 2024 07:12
Date Deposited: 19 Aug 2019 09:37
Full Text Link: http://link.spr ... 0726-015-2063-5
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2016-01
Published Online Date: 2015-08-07
Accepted Date: 2015-08-01
Authors: Kiraly, Robert
Thangaraju,, Kiruphagaran
Nagy, Zsófia
Collighan, Russell (ORCID Profile 0000-0003-0204-5125)
Nemes, Zoltán
Griffin, Martin (ORCID Profile 0000-0003-3824-306X)
Fésüs, László



Version: Accepted Version

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