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OPTIMIZATION OF THE PHOTO‐ENZYMATIC REDUCTION OF THE CARBON‐CARBON DOUBLE BOND OF α‐β UNSATURATED CARBOXYLATES IN REVERSED MICELLES
Author(s) -
VERHAERT R. M. D.,
SCHAAFSMA T. J.,
LAANEI C.,
HILHORST R.,
VEEGER C.
Publication year - 1989
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1989.tb04098.x
Subject(s) - chemistry , micelle , photochemistry , aqueous solution , electron donor , photosensitizer , micellar solutions , electron acceptor , organic chemistry , catalysis
A system is described for the photo‐induced biocatalytic reduction of enoates in reversed micelles composed of detergent, buffer and mixtures of alcohol and octane as cosurfactant and dispersant respectively. The photosystem consisted of the sacrificial electron donor tributylamine, Zn(II) meso ‐mono(4‐N‐decyipyridyl)‐tri(phenyl)porphyrin as photosensitizer and methylviologen as electron acceptor. The enzyme enoate reductase (EC 1.3.1.31) utilizes the photo‐reduced methylviologen for the stereospecific reduction of enoates. The composition of the reversed micellar medium has been optimized with respect to both the photochemical and the enzymatic part of the system. The yield of the photosystem increased with increasing polarity of the reversed micellar solution. The activity and stability of enoate reductase depended strongly on the nature and concentration of the cosurfactant in the reversed micelles. Increasing the chain length of the cosurfactant stabilizes the enzyme in the presence of enoates, but it leads to a more rapid loss of activity of the reduced form of the enzyme. Reversed micelles were composed in which both operational and storage stability of enoate reductase are at least equal to that in water. The photochemical regeneration of methylviologen coupled to the enzymatic reduction of tiglic acid and cinnamic acid yielded a system that was active for over 100 h in the presence of a cofactor regenerating system in reversed micelles. The enzyme was as stable as in aqueous solution. Therefore this photo‐enzymatic system can be used for the stereospecific reduction of apolar α‐β unsaturated carboxylates.