IUBMB Enzyme Nomenclature


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 quinohaemoprotein. Also contains a single haem 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.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


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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