Distribution of amine oxidases and amine dehydrogenases in bacteria grown on primary arnines and characterization of the arnine oxidase f rom Klebsiella oxytoca

Department of Microbiology and Enzymology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands The bacteria Klebsiella oxytoca LMD 72.65 (ATCC 8724), Arthrobacter PI LMD 81.60 (NCIB 11 625), Paracoccus wersutus LMD 80.62 (ATCC 25364), Escherichia coli W LMD 50.28 (ATCC 9637), E. coli K12 LMD 93.68, Pseudomonas aeruginosa PA01 LMD 89.1 (ATCC 17933) and Pseudomonas putida LMD 68.20 (ATCC 12633) utilized primary amines as a carbon and energy source, although the range of amines accepted varied from organism to organism. The Gram-negative bacteria K. oxytoca and E. coli as well as the Gram-positive methylotroph Arthrobacter P I used an oxidase whereas the pseudomonads and the Gramnegative methylotroph Paracoccus wersutus used a dehydrogenase for amine oxidation. K. oxytoca utilized several primary amines but showed a preference for those containing a phenyl group moiety. Only a single oxidase was used for oxidation of the amines. After purification, the following characteristics of the enzyme indicated that it belonged t o the group of copper-quinoprotein amine oxidases (EC 1.4.3.6) : the molecular mass (172 000 Da) of the homodimeric protein; the UWvisible and EPR spectra of isolated and pnitrophenylhydrazine-inhibited enzyme; the presence and the content of copper and topaquinone (TPQ). The amine oxidase appeared to be soluble and localized in the periplasm, but catalase and NAD-dependent aromatic aldehyde dehydrogenase, enzymes catalysing the conversion of its reaction products, were found in the cytoplasm. From the amino acid sequence of the N-terminal part as well as that of a purified peptide, it appears that K. oxytoca produces a copper-quinoprotein oxidase which is very similar to that found in other Enterobacteriaceae.