Table 5.

Product formationa by wild-type and hybrid dioxygenases

DioxygenaseAmt (μg/ml) of:
cis-Naphthalene dihydrodiol from NAP2-Nitrobenzyl alcohol from 2NTb4-Methyl-5-nitrocatechol from DNT
NDO80033.4 —c
NDO-β2NTDO 27935.4
NDO-βDNTDO 1138.7
NDO-βTDO  NDd ND
NDO-β0
DNTDO96.9Tracee 18.8
DNTDO-β2NTDO 32.34.9
DNTDO-βNDO
DNTDO-βTDO NDND
DNTDO-β0
  • a Products formed from naphthalene (NAP), 2-nitrotoluene (2NT) and 2,4-dinitrotoluene (DNT) were detected and quantified by HPLC after 5-h biotransformations. Data presented are from one of at least two similar experiments.

  • b No 3-methylcatechol was detected in any 2NT biotransformations, although control DH5α(pDTG800), which produces wild-type 2NTDO, formed 3-methylcatechol and 2-nitrobenzyl alcohol in a 9:1 ratio.

  • c —, no products were detected by HPLC analysis of 5-h aqueous samples or by GC-MS after extraction and concentration of 24-h biotransformation samples.

  • d ND, not determined.

  • e Detected by GC-MS after extraction and concentration of 24-h biotransformation samples. Not detected in aqueous samples by HPLC, where the limits of detection forcis-naphthalene dihydrodiol, 2-nitrobenzyl alcohol, and 4-methyl-5-nitrocatechol were each approximately 2 μg/ml.