Covalent binding, redox mediators

Scheme 11. Idealized sketch showing the electroen matic oxidation of L-lactate at gold modified electrode surfaces, (a) Lactate dehydrogenase bound to CB-terminated alkylthiol SAMs prepared by covalent attachment of CB to 3-mercaptopropionic acid SAM derivatized with 1,4-diaminobutane. The electroenzymatic oxidation of lactate is observed only in the presence of soluble coenzyme (NAD" ") and a redox mediator (phenazine methosulfate) [215]. (b) Lactate deh3tdrogenase bound to NAD-terminated alkylthiol SAMs prepared by covalent attachment of Af -(2-aminoethyl)-NAD to a cystamine SAM derivatized with pjrrroloquinoline quinone. The reconstituted enzyme is electrically wired to the electrode surface via two NAD" -binding pockets involved in the affinity-binding surface reaction [242].

Modification of Enzymes by Covalent Binding of Redox Mediators... 

For the construction of reagentless en e electrodes one has to focus on a technique for the modification and functionalization of electrode and even micro-electrode surfaces to allow the covalent binding of the enzyme and the redox mediator taking into account the presuppositions for an dOfective and fiist electron transfer between the enzyme and the electrode. 

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