Two Proteins with Diaphorase Activity from Clostridium thermocellum and Moorella thermoacetica

Abstract

Two high-molecular-weight rubredoxin genes (hrb) from Clostridium thermocellum and Moorella thermoacetica were expressed in Escherichia coli and their translated products (Hrb) were characterized. M. thermoacetica Hrb showed strong diaphorase activity. In contrast, C. thermocellum Hrb, containing neither FMN nor FAD in the molecule, showed flavin reductase activity with moderate diaphorase activity. Both enzymes were optimally active at about 50 °C.