Purification and properties of glucose dehydrogenase and cytochrome b from Bacterium anitratum

Abstract

A soluble glucose dehydrogenase with a turnover number of 28,000 moles of glucose/min per 10 5 g of protein has been purified from Bacterium anitratum. The enzyme does not posess a flavin or heme prosthetic group. It catalyzes the reduction of 2,6-dichlorophenolindophenol and phenazine methosulphate well, but ferricyanide and methylene blue only very slowly. Reduction of DPN, TPN, FMN, FAD, cytochrome c, tetrazolium, or oxygen could not be detected. The dehydrogenase was accompanied during all purification steps except the last by a b-type cytochrome with absorption maxima at 419 and 530 mμ in the oxidized state, 428, 532, and 562 mμ in the reduced. It was purified to the stage of 2.9·10 5 g protein per mole of protoporphyrin. In the presence of the dehydrogenase and possible unidentified linking factors, the hemoprotein was reduced by glucose. Evidence is presented and the possibility discussed that the two proteins are soluble precursors or degradation products of the particulate glucose oxidizing system from the same organism.