OCCURRENCE OF INDUCIBLE AND NAD(P)-INDEPENDENT PRIMARY ALCOHOL DEHYDROGENASES IN AN ALKANE-OXIDIZING PSEUDOMONAS

Pseudomonas aeruginosa (strain 473) constitutively contains a soluble NADP-linked dehydrogenase active towards primary alcohols. In addition, at least two NAD(P)-independent primary alcohol dehydrogenases can be induced by growing this strain on primary alcohols, α,ω-diols or n-alkanes. These inducible enzymes were found to be bound to cellular structures. They reduce bovine cytochrome c and various dyes, but not oxygen. The main difference between the inducible enzymes is their different capacity to oxidize ethanol. Noteworthy properties of the enzymes are: 1) the affinities for the straight-chain primary alcohols increase with increasing chain length (tested up to 1-decanol); 2) the affinities decrease when polar atoms or groups are introduced into the alcohol molecule; 3) enzyme preparations as well as intact cells, when provided with a mixture of alcohols, first oxidize the compound with the lowest solubility in water. These properties can be explained by assuming that hydrophobic bonds are formed between the enzyme and aliphatic parts of the alcohol molecule. © 1969 Swets & Zeitlinger.