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Substrate Desolvation as a Governing Factor in Enzymatic Transformations of PAHs in Aqueous‐Acetonitrile Mixtures
Author(s) -
Borole Abhijeet P.,
Cheng Catherine L.,
Davison Brian H.
Publication year - 2004
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp034302r
Subject(s) - pyrene , chemistry , aqueous solution , acetonitrile , substrate (aquarium) , solvent , aqueous medium , organic solvent , chemical engineering , organic chemistry , oceanography , engineering , geology
Conversion of hydrophobic substrates such as polyaromatic hydrocarbons (PAHs) was studied in aqueous‐organic media using transformation of pyrene by cytochrome c . The experiments were conducted in pure solvents and aqueous‐acetonitrile mixtures. The reaction rates dropped gradually as the solvent concentration was increased and were negligible in pure solvents. Thermodynamic calculations show that substrate desolvation was the governing factor in this reaction. The decrease in free energy of activation upon increasing the solvent concentration was found to be proportional to the substrate transfer free energy. This suggests that in order to make such reactions feasible in organic media, it will be necessary to improve the binding between the proteins and the substrates.