反应详情

As a diagnostic reaction to assess similarities or differences between aromatic dioxygenases from the present heterocyclic indole oxidase, crude SCF as prepared in Example 6 was tested in its ability to oxidatively transform indene. This was carried out under conditions identical to those described in Example 9 for indigo accumulation. Indene removal from reaction mixtures was evident from GC/MS analyses (see Materials and Method Section above). A single detectable product accumulated constituting approximately 20% of the total ion current. This product had a retention time of 7.5 min and its mass spectrum exhibited a molecular ion at m/z=132. Both the retention time and mass spectrum of this product were identical to those of authentic 2-indanone. The identification of 2-indanone as the sole product from indene demonstrates a major difference between the indole oxidation activity in strain WW2 and the well characterized toluene and naphthalene dioxygenase systems. The latter have been shown to oxidize indene to cis-1,2-indandiol and 1-indenol in about equal amounts (Gibson, D. T., S. M. Resnick, K. Lee, J. M. Brand, D. S. Torok, L. P. Wackett, M. J. Schocken, B. E. Haigler (1995) “Desaturation, dioxygenation and monooxygenation reactions catalyzed by naphthalene dioxygenase from Pseudomonas sp. strain 9816-4,” J. Bacteriol. 177:2615-2621). Neither toluene nor naphthalene dioxygenase form 2-indanone. It is also notable that the 2-indanone formed by strain WW2 SCF accumulates and does not appear to be further oxidized. Naphthalene dioxygenase has been shown to oxidize 2-indanone to 2-hydroxy-1-indanone (Resnick, S. M., D. S. Torok, K. Lee, J. M. Brand, D. T. Gibson (1994) “Regiospecific and stereoselective hydroxylation of 1-indanone and 2-indanone by naphthalene dioxygenase and toluene dioxygenase,” Appl. Environ. Microbiol. 60:3323-3328); this product was not observed in the present study.

1. customformed by strain WW2 SCF accumulates