Journal
BIOTECHNOLOGY JOURNAL
Volume 5, Issue 8, Pages 822-828Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/biot.201000119
Keywords
Ferricyanide; Glucose dehydrogenase; PQQ; Mediator
Funding
- Lithuanian State Science and Studies Foundation [N-08007]
Ask authors/readers for more resources
Pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase (PQQ-GDH) offers a variety of opportunities for applications, e.g. in highly sensitive biosensors and electrosynthetic reactions Here we report on the acceleration (up to 4 9 x 10(4)-fold) of enzymatic ferricyanide reduction by artificial redox mediators (enhancers). The reaction mechanism includes reduction of the PQQ-GDH by glucose followed by oxidation of the reduced PQQ cofactor with either ferricyanide or a redox mediator A synergistic effect occurs through the oxidation of a reduced mediator by ferricyanide Using kinetic description of the coupled reaction, the second order rate constant for the reaction of an oxidized mediator with the reduced enzyme cofactor (k(ox)) can be calculated For different mediators this value is 2 2 x 10(6)-1 6 x 10(8) M(-1)s(-1) at pH 7 2 and 25 degrees C However, no correlation of the rate constant with the midpoint redox potential of the mediator could be established For low-potential mediators the synergistic effect is proportional to the ratio of k(ox(med))/k(ox(ferricyanide)), whereas for the high-potential mediators the effect depends on both this ratio and the concentration of the oxidized mediator, which can be calculated from the Nernst equation The described effect can be applied in various ways, e g. for substrate reactivity determination, electrosynthetic PQQ cofactor regeneration or building of new highly sensitive biosensors
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available