Stimulatory factors for enzymatic biotin synthesis from dethiobiotin in cell-free extracts of Escherichia coli.

The activity of biotin synthesis from dethiobiotin was found in cell-free extracts of an Escherichia coli bioB transformant. Among the sulfur compounds tested, only S-adenosyl-L-methionine (AdoMet) had a significant effect, while methionine and cysteine were inert. The activity was linearly stimulated by increasing protein concentration. When the dialyzed cell-free extracts were used for the reaction, NADP+, NADPH, and FAD among the well-known cofactors tested promoted the activity. Furthermore, in the presence of AdoMet, cysteine was apparently effective for biotin synthetic activity.