Theoretical estimation of the dielectric properties of an enzyme active site
- 1 January 1997
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 93 (1) , 99-103
- https://doi.org/10.1039/a604844g
Abstract
A theoretical investigation of the solvatochromism of 4-carbamidopyridinium cyclopentadienylide (CPCP) has been carried out to understand the environmental effect of the enzyme active site. The λ max values for CPCP in various solvents and in the binding pocket of horse liver alcohol dehydrogenase (LADH) have been calculated using the INDO/S method. Since the shape of CPCP is not spherical, the cavity radius was considered as an adjustable parameter that controls the strength of the reaction field in the INDO/S calculation. To investigate the medium effect of the enzyme binding pocket correctly, the specific interaction, such as a ligation of Zn 2+ , should be considered in the calculation of the λ max values. By comparing the experimental λ max value for CPCP in LADH with the calculated values for the Zn 2+ –(SH) 2 –Im–CPCP complex, we have found that the medium effect of the LADH binding pocket is similar to that of organic solvents such as octan-1-ol(ε=10.3) and CH 2 Cl 2 (ε=8.9).Keywords
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