Plasmid dependence of Pseudomonas sp. strain NK87 enzymes that degrade 6-aminohexanoate-cyclic dimer

J Bacteriol. 1989 Jun;171(6):3181-6. doi: 10.1128/jb.171.6.3181-3186.1989.


A bacterial strain, Pseudomonas sp. strain NK87, that can use 6-aminohexanoate-cyclic dimer as the sole source of carbon and nitrogen was newly isolated from wastewater of a factory which produces nylon-6. Two responsible enzymes, 6-aminohexanoate-cyclic-dimer hydrolase (P-EI) and 6-aminohexanoate-dimer hydrolase (P-EII), were found in the NK87 strain, as is the case with Flavobacterium sp. strain KI72, another 6-aminohexanoate-cyclic-dimer-metabolizing bacterium (H. Okada, S. Negoro, H. Kimura, and S. Nakamura, Nature [London] 306:203-206, 1983). The P-EI enzyme is immunologically identical to the 6-aminohexanoate-cyclic-dimer hydrolase of KI72 (F-EI). However, antiserum against the 6-aminohexanoate-dimer hydrolase purified from KI72 (F-EII) did not react with cell extracts of NK87, indicating that the F-EII and P-EII enzymes are immunologically different. Restriction endonuclease analyses show that the NK87 strain harbors at least six plasmids ranging in size from 20 to 80 kilobase pairs (kbp). The P-EI and P-EII genes were cloned in Escherichia coli. Both the P-EI and F-EI probes strongly hybridized with a 23-kbp plasmid in Southern hybridization analyses. The P-EII probe hybridized specifically with an 80-kbp plasmid, but the F-EII probe hybridized with none of the plasmids harbored in NK87. These results indicate that the P-EI gene and P-EII gene are encoded on the 23-kbp and 80-kbp plasmids, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amidohydrolases / genetics*
  • Amidohydrolases / immunology
  • Amidohydrolases / metabolism
  • Blotting, Southern
  • Cloning, Molecular
  • DNA, Bacterial
  • Genes, Bacterial
  • Nylons / metabolism
  • Plasmids
  • Pseudomonas / enzymology*
  • Pseudomonas / genetics
  • Pseudomonas / metabolism
  • Restriction Mapping
  • Xenobiotics / metabolism


  • DNA, Bacterial
  • Nylons
  • Xenobiotics
  • Amidohydrolases
  • 6-aminohexanoate-cyclic-dimer hydrolase