Catalyzes the oxidation of ethanol and other primary alcohols to the corresponding aldehydes, except methanol, which is a very poor substrate. Uses a specific inducible cytochrome c550, encoded by the adjacent gene in the locus, as electron acceptor. Is a key enzyme of the carbon and energy metabolism during growth of P.aeruginosa on ethanol as the sole carbon and energy source. Is also able to use secondary alcohols as well as aminoalcohols like ethanolamine and 1-amino-2-propanol, and aldehydes as substrates. a primary alcohol + 2 Fe(III)-[cytochrome c] = an aldehyde + 2 Fe(II)-[cytochrome c] + 2 H(+) ethanol + 2 Fe(III)-[cytochrome c] = acetaldehyde + 2 Fe(II)-[cytochrome c] + 2 H(+) butan-1-ol + 2 Fe(III)-[cytochrome c] = butanal + 2 Fe(II)-[cytochrome c] + 2 H(+) 2 Fe(III)-[cytochrome c] + propan-2-ol = acetone + 2 Fe(II)-[cytochrome c] + 2 H(+) 1-propanol + 2 Fe(III)-[cytochrome c] = 2 Fe(II)-[cytochrome c] + 2 H(+) + propanal Binds 1 PQQ group non-covalently per subunit (PubMed:10736230, PubMed:3144289). PQQ is embedded between the ring structure formed from a disulfide bridge between adjacent cysteines Cys-139 and Cys-140 and the indole ring of Trp-282 (PubMed:10736230). Binds 2 calcium ions per subunit. One is located in the active-site cavity near PQQ and the second calcium binds at the N-terminus and contributes to the stability of the native enzyme. Inhibited by cyclopropanone ethylhemiketal. Activated by ammonia (500mM), methylamine (5mM), ethylamine (5mM), octylamine (5mM), ethanolamine (5mM) and 1-amino-2-propanol (5mM), in assays using artificial electron acceptors (PubMed:3144289). Ammonia is not needed for, nor does it stimulate, the ethanol-oxidizing activity when using the natural electron acceptor cytochrome c550 (PubMed:8380982). kcat is 11 sec(-1) for the oxidation of ethanol using artificial electron acceptor (at pH 9). kcat is 15 sec(-1) for the oxidation of 1-propanol using artificial electron acceptor (at pH 9). kcat is 11 sec(-1) for the oxidation of 2-propanol using artificial electron acceptor (at pH 9). kcat is 40 sec(-1) for the oxidation of 1,3-propanediol using artificial electron acceptor (at pH 9). kcat is 42 sec(-1) for the oxidation of 1-butanol using artificial electron acceptor (at pH 9). kcat is 2.4 sec(-1) for the oxidation of 2-propanol using natural electron acceptor cytochrome c550 (at pH 7). Optimum pH is 9 in assays using artificial electron acceptors (PubMed:3144289). However, in a system with homogenous QEDH, cytochrome c550 and a membrane fraction of P.aeruginosa, electron transport from ethanol to O(2) is observed at the more physiological conditions of pH 7, and the system is inactive at pH 9 (PubMed:8380982). Alcohol metabolism; ethanol degradation; acetate from ethanol: step 1/2. Homodimer. Interacts with cytochrome c550 (PubMed:19224199). Induced by growth on ethanol. The disulfide ring formed between the two adjacent cysteine residues Cys-139 and Cys-140 is essential for efficient electron transfer at pH 7 from QEDH to its natural electron acceptor cytochrome c550. Belongs to the bacterial PQQ dehydrogenase family.