INVOLVEMENT OF FLAVIN COENZYME IN DIBENZOTHIOPHENE DEGRADING ENZYME-SYSTEM FROM RHODOCOCCUS-ERYTHROPOLIS D-1

In the process of the purification of a dibenzothiophene (DBT)-degradi ng enzyme system from cell-free extracts of Rhodococcus erythropolis D -1, flavin coenzymes, FMN and PAD, were found to be involved in the en zymatic degradation of DBT in addition to NADH. Under these experiment al conditions, the optimal concentrations of FMN and FAD were both 10 mu M and the activity was completely inhibited by adding 1 mM FMN or F AD. DBT was converted to DBT sulfone stoichiometrically and 2-hydroxyb iphenyl formation was not observed when the reaction was done using th e enzyme preparation purified by DEAE-Sepharose column chromatography.