Accepted name: alcohol dehydrogenase (azurin)
Reaction: a primary alcohol + azurin = an aldehyde + reduced azurin
Other name(s): type II quinoprotein alcohol dehydrogenase; quinohaemoprotein ethanol dehydrogenase; QHEDH; ADHIIB
Systematic name: alcohol:azurin oxidoreductase
Comments: A soluble, periplasmic PQQ-containing quinohemoprotein. Also contains a single heme c. Occurs in Comamonas and Pseudomonas. Does not require an amine activator. Oxidizes a wide range of primary and secondary alcohols, and also aldehydes and large substrates such as sterols; methanol is not a substrate. Usually assayed with phenazine methosulfate or ferricyanide. Like all other quinoprotein alcohol dehydrogenases it has an 8-bladed ‘propeller’ structure, a calcium ion bound to the PQQ in the active site and an unusual disulfide ring structure in close proximity to the PQQ.
1.  Groen, B.W., van Kleef, M.A. and Duine, J.A. Quinohaemoprotein alcohol dehydrogenase apoenzyme from Pseudomonas testosteroni. Biochem. J. 234 (1986) 611–615. [PMID: 3521592]
2.  de Jong, G.A., Caldeira, J., Sun, J., Jongejan, J.A., de Vries, S., Loehr, T.M., Moura, I., Moura, J.J. and Duine, J.A. Characterization of the interaction between PQQ and heme c in the quinohemoprotein ethanol dehydrogenase from Comamonas testosteroni. Biochemistry 34 (1995) 9451–9458. [PMID: 7626615]
3.  Toyama, H., Fujii, A., Matsushita, K., Shinagawa, E., Ameyama, M. and Adachi, O. Three distinct quinoprotein alcohol dehydrogenases are expressed when Pseudomonas putida is grown on different alcohols. J. Bacteriol. 177 (1995) 2442–2450. [PMID: 7730276]
4.  Matsushita, K., Yamashita, T., Aoki, N., Toyama, H. and Adachi, O. Electron transfer from quinohemoprotein alcohol dehydrogenase to blue copper protein azurin in the alcohol oxidase respiratory chain of Pseudomonas putida HK5. Biochemistry 38 (1999) 6111–6118. [PMID: 10320337]
5.  Chen, Z.W., Matsushita, K., Yamashita, T., Fujii, T.A., Toyama, H., Adachi, O., Bellamy, H.D. and Mathews, F.S. Structure at 1.9 Å resolution of a quinohemoprotein alcohol dehydrogenase from Pseudomonas putida HK5. Structure 10 (2002) 837–849. [PMID: 12057198]
6.  Oubrie, A., Rozeboom, H.J., Kalk, K.H., Huizinga, E.G. and Dijkstra, B.W. Crystal structure of quinohemoprotein alcohol dehydrogenase from Comamonas testosteroni: structural basis for substrate oxidation and electron transfer. J. Biol. Chem. 277 (2002) 3727–3732. [PMID: 11714714]
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