Author(s): Oppenheim SF, Studts JM, Fox BG, Dordick JS
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Abstract Toluene 4-monooxygenase is a four-protein component diiron enzyme complex. The enzyme catalyzes the hydroxylation of toluene to give p-cresol with approximately 96\% regioselectivity. The performance of the enzyme in two-phase reaction systems consisting of toluene, hexane, or perfluorohexane and an aqueous buffer was tested. In each of the cosolvent systems, containing up to 93\% (v/v) of solvent, the enzyme was active and exhibited regioselectivity indistinguishable from the aqueous reaction. Using the perfluorohexane/buffer system, a number of polycyclic aromatic hydrocarbons were oxidized that were not readily oxidized in aqueous buffer. An instability of the hydroxylase component and a substantial uncoupling of NADH utilization and product formation were observed in reactions that were continued for longer than approximately 3 min. More stable enzyme complexes will be needed for broad applicability of this hydroxylating system in nonaqueous media.
This article was published in Appl Biochem Biotechnol
and referenced in Industrial Engineering & Management