Involvement of Flavin Coenzyme in Dibenzothiophene Degrading Enzyme System from Rhodococcus erythropolis D-1

In the process of the purification of a dibenzothiophene (DBT)degrading enzyme system from cell-free extracts of Rhodococcus erythropolis D-1, flavin coenzymes, FMN and FAD, were found to be involved in the enzymatic degradation of DBT in addition to NADH. Under these experimental conditions, the optimal concentrations of FMN and FAD were both 10 µM and the activity was completely inhibited by adding 1 mM FMN or FAD. DBT was converted to DBT sulfone stoichiometrically and 2-hydroxybiphenyl formation was not observed when the reaction was done using the enzyme preparation purified by DEAE-Sepharose column chromatography.