A polyol dehydrogenase responsible for the conversion of acyclic polyol to the corresponding ketoses was isolated and partially purified from cell free extracts of acetic acid bacteria, $\mbox{\underline{Gluconobatacter}}$ $\mbox{\underline{melanogenus}}$, and its general properties were characterized.
The enzyme was found to be aerobic in nature and to utilized 2.6-dichlorophenolindophenol as an external electron acceptor for the specific oxido-reduction reaction.
No requirement of pyridine nucleotide coenzyme was found for the conversion of D-sorbitol to L-Sorbose.
The enzyme was found to be different from the other polyo1 dehydrogenase requiring $NAD^+$ as a cofactor for the enzyme activities.
The enzyme showed a broad substrate specificity, but seems to be very specific towards acyclic polyols having the L-erythro configulation.
The Km values for D-sorbitol and D-mannitol were obtained as $3.8 ×10^{-1}$M and $4.0 ×10^{-2}$M, respecively.
The maximum activity of the enzyme was obtained at $p^H$ 5.4 and 30C. The enzyme was inhibited by iodoac etamide and heavy metal ions ($Ag^+$ and $Hg^{++}$ ions) remarkably.
The results from inhibition study with substrate analogous and other inhibitors for biological oxidative reaction suggest that the enzyme may possibly be linked to cytochrom a and b in a membrane bound respiratory chain.
Gluconobacter melanogenus 를 D-sorbitol 를 탄소원으로 한 배지에서 배양한 균체를 초음파 처리하여 얻은 추출액을 $(NH_4)_2 SO_4$ 침전에 의하여 분획할때 0-40% 침전 중에서 nicotinamide nucleotide independent polyol dehydrogenase 활성을 발견하였다. 이 효소의 반응 생성물을 paper chromatography 방법과 cysteine-Sulfuric acid 방법에 의해서 확인한 결과 D-sorbitol 과 D-mannitol 은 각각 L-sorbose 와 D-fructose 로 산화되었다.
이 효소는 인공전자 수용체인 2.6 Dichlorophenol 과 ferricyanide 를 환원시켰는데 그중에서 2.6 Dichlorophenol indophenol 의 환원을 이용하여 효소 활성도 측정을 할수 있었다.
이러한 효소활성도 측정방법에 의해서 측정한 결과 최적 pH 는 5.4 였으며 D-Sorbitol에 대한 Km 은 $3.8 × 10^{-2}M$ 이었다. D-sorbitol, D-mannitol 과 아울러 i-erythritol, D-arabitol, D-adonitol에도 작용하는 L-erythro configulation 기질특이성을 갖고 있었다.
D-sorbitol의 산화가 일어날때 산소를 필요로 했으며 이때 흡수된 산소 1 mole 에 대해 L-sorbose가 2 mole 생성되었다.
효소반응에 있어서 산소로의 전자전달은 Cyt a와 Cyt b 를 포함하는 것으로 예상되는 호흡연쇄계를 통하여 일어나는 것으로 나타났다.
