Catalytic Water Oxidation by Iridium-Modified Carbonic Anhydrase

Min Chul Kim, Sang Yup Lee

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Carbonic anhydrase (CA) is a ubiquitous metalloenzyme with a Zn cofactor coordinated to trigonal histidine imidazole moieties in a tetrahedral geometry. Removal of the Zn cofactor in CA and subsequent binding of Ir afforded CA[Ir]. Under mild and neutral conditions (30 °C, pH 7), CA[Ir] exhibited water-oxidizing activity with a turnover frequency (TOF) of 39.8 min−1, which is comparable to those of other Ir-based molecular catalysts. Coordination of Ir to the apoprotein of CA is thermodynamically preferred and is associated with an exothermic energy change (ΔH) of −10.8 kcal mol−1, which implies that the CA apoprotein is stabilized by Ir binding. The catalytic oxygen-evolving activity of CA[Ir] is displayed only if Ir is bound to CA, which functions as an effective biological scaffold that activates the Ir center for catalysis. The results of this study indicate that the histidine imidazoles at the CA active site could be exploited as beneficial biological ligands to provide unforeseen biochemical activity by coordination to a variety of transition-metal ions.

Original languageEnglish
Pages (from-to)334-341
Number of pages8
JournalChemistry - An Asian Journal
Issue number3
Publication statusPublished - 2018 Feb 2

Bibliographical note

Funding Information:
This work was supported by a grant from the Korean Research Foundation funded by the Korean Government (NRF-2016R1D1A1A09917929) and by the Human Resources Program in Energy Technology of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), a granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20154010200810).

Publisher Copyright:
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Organic Chemistry


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