Microbial transformation of rifamycin B: A new synthetic approach to rifamycin derivatives.

Biotransformations of rifamycins: Process possibilities

“…are different from that The catalytic properties of partially purified rifamycin oxidase produced intracellularly by Humicola sp. were reported by Seong et al [25]. The enzyme was most specific for rifamycin B among the various rifamycin derivatives tested [26].…”

“…The Kin-value of this enzyme from Humicola sp. was found to be 0.05 mM [25]. Substrate inhibition was observed at substrate concentrations above 2 mM.…”

“…A pH of 7.8 and a temperature of 45 ° C were optimal for enzyme activity, catalytic activity was greatly reduced above this temperature. The rifamycin oxidase activity was strongly inhibited by Fe +2 and Hg +2, but not by other metal ions [25]. Presence of chelating agents such as EDTA did not affect the enzyme activity [25].…”

“…and its morphological and culture characteristics [20]. They further demonstrated that rifamycin S can be prepared in high yield by microbial transformation of rifamycin B [20].…”

“…P-hydroxyphenoxyacetic acid and p-hydroquinone which are corresponding structural analogues in the quinonoid moiety, caused a significant decrease in the enzyme activity compared to rifamycin B and rifamycin SV, respectively [25]. The enzyme showed highest catalytic activity on rifamycin B among the various substrates used.…”