Pyrroloquinoline quinone dependent alcohol dehydrogenase

Matsushita K, Takaki Y, Shinagawa E, Ameyama M, Adachi O (1992) Ethanol oxidase respiratory chain of acetic acid bacteria. Reactivity with ubiquinone of pyrroloquinoline quinone-dependent alcohol dehydrogenases purified from Acetobacter aceti and Gluconobacter suboxydans. Biosci Biotechnol Biochem 56(2) 304-310... 

Shimao M, Tamogami T, Nishi K, Harayama S (1996) Cloning and characterization of the gene encoding pyrroloquinoline quinone-dependent poly(vinyl alcohol) dehydrogenase of Pseudomonas sp. strain VM15C. Biosci Biotechnol Biochem 60 1056-1062... 

Shimao M, Ninomiya K, Kuno O, Kato N, Sakazawa C (1986), Existence of a novel enzyme, pyrroloquinoline quinone-dependent polyvinyl alcohol dehydrogenase, in a bacterial symbiont. Pseudomonas sp. strain VM15C , Appl Environ Microbiol, 51, 268-275. 

An alternative biosensor system has been developed by Hart et al. [44] which involves the use of the NAD+-dependent GDH enzyme. The first step of the reaction scheme involves the enzymatic reduction of NAD+ to NADH, which is bought about by the action of GDH on glucose. The analytical signal arises from the electrocatalytic oxidation of NADH back to NAD+ in the presence of the electrocatalyst Meldola s Blue (MB), at a potential of only 0Y. Biosensors utilising this mediator have been reviewed elsewhere [1,17]. Razumiene et al. [45] employed a similar system using both GDH and alcohol dehydrogenase with the cofactor pyrroloquinoline quinone (PQQ), the oxidation of which was mediated by a ferrocene derivative. 

Quinoproteins constitute a class of dehydrogenases distinct from the nicotinamide-and flavin-dependent oxidoreductases 11691. They use different quinone cofactors to convert a vast variety of alcohols and amines into their corresponding carbonyl products11701. Proteins containing the cofactor pyrroloquinoline quinone (PQQ) (Fig. 16.2-36) form the largest and best-characterized sub-group. 

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