Abstract
Particulate alcohol dehydrogenase of acetic acid bacteria that is mainly participated in vinegar fermentation was purified to homogeneous state from Gluconobacter suboxydans IFO 12528. Solubilization of enzyme from the bacterial membrane fraction by Triton X-100 and subsequent fractionation on DEAE-Sephadex A-50 and hydroxylapatite was successful in enzyme purification. A cytochrome c-like component was tightly bound to the dehydro-genase protein and existed as an enzyme-cytochrome complex. It was also confirmed that the alcohol dehydrogenase is not a cytochrome component itself. The molecular weight of the enzyme was determined to be 150, 000, and gel electrophoresis showed the presence of three subunits having a molecular weight of 85, 000, 49, 000 and 14, 400. The smallest subunit was corresponded to the cytochrome c-like component. Ethanol was oxidized in the presence of dyes in vitro but NAD or NADP were not required as hydrogen acceptor. Unlike NAD-linked alcohol dehydrogenase in yeast or liver and other primary alcohol dehydrogenases in methanol utilizing bacteria, the enzyme from the acetic acid bacteria showed its optimum pH at fairly acidic pH.
