Recently, a new catalyst that mimics carbonic anhydrase (CA) was constructed by the self-assembly of histidyl bolaamphiphilic molecules and a Zn ion cofactor. The catalytic Zn ion complex in a tetrahedral coordination geometry is composed of self-organized histidyl imidazoles and a single hydroxide ion. However, the Zn-hydroxide coordination, the key structure of the catalytic analogue, is disturbed by the pairing anion of the Zn salt. Here, the performances of the CA-mimicking catalysts prepared from various Zn salts were examined along with CO2 hydration. Among the Zn salts with different anions, Zn(OH)2 showed the highest catalytic performance with increased CO2 hydrolysis activity. Spectroscopic and thermodynamic analyses proved the formation of histidine-Zn-hydroxide coordination with a lowered activation energy if Zn(OH)2 was used. With regard to the anion interaction with the Zn ion, the catalytic performance is inversely proportional to the solution dissociation energy of the Zn salt. Zinc about it: Among the various Zn salts used for the preparation of a catalyst that mimics carbonic anhydrase (CA), Zn(OH)2 shows the highest catalytic performance with increased hydrolysis activity as it minimizes the interference of the counter anion. Spectroscopic analysis and calculated activation energies along with practical CO2 sequestration of the CA-mimetic catalysts confirms catalysis inhibition by Zn-binding anions.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry