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Micelle‐supported electroenzymology: Succinate dehydrogenation by escherichia coli fumarate reductase in decylubiquinone and octyl glucoside micelles
Author(s) -
Kinnear Kathleen T.,
Monbouquette Harold G.
Publication year - 1993
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260420119
Subject(s) - micelle , chemistry , fumarate reductase , succinate dehydrogenase , cyclic voltammetry , pulmonary surfactant , critical micelle concentration , electrochemistry , enzyme , inorganic chemistry , dehydrogenation , vesicle , reductase , organic chemistry , membrane , nuclear chemistry , electrode , aqueous solution , catalysis , biochemistry
The concept of micelle‐supported electroenzymology is demonstrated using a system consisting of the membrane enzyme Escherichia coli fumarate reductase (FRD), the amphiphilic coenzyme analogue decylubiquinone (DU), the micelle‐forming surfactant n ‐octyl glucoside (OG), and a gold electrode. The OG micelles provide a hydrophobic, membrane mimetic medium for FRD and DU to exchange electrons while the gold electrode serves to regenerate DU. When succinate is presented to the FRD/DU/OG micelle system, electroenzymatic oxidation of succinate to fumarate occurs as evidenced using cyclic voltammetry. DU is shown to be the only electroactive species in the system; and as increasing amounts of succinate are added, the expected increase in the peak anodic (oxidative) current and decrease in the peak cathodic (reductive) current are observed. The peak anodic current approaches a limiting value with succinate concentration in qualitative agreement with simple Michaelis–Menten enzyme kinetics. When the strong competitive inhibitor oxaloacetate is added, enzymatic oxidation of succinate is inhibited as indicated by no change in the peak anodic and cathodic currents with increasing succinate concentration. © 1993 John Wiley & Sons, Inc.