The Redox Reactions in Propionic Acid Fermentation
IV. Participation of Menaquinone in the Electron Transfer System in Propionibacterium arabinosum
1974 Volume 76 Issue 1 Pages 137-145
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1974 Volume 76 Issue 1 Pages 137-145
The functions of menaquinone in the electron transfer system in Propinoibacterium arabinosum were examined.
1. Activities for reactions such as NADH oxidation, fumarate reductions with MADH, glycerol-P and lactate, and the glycerol-P dehydrogenase reaction were rapidly lost when the membrane preparation from P. arabinosum was irradiated with near-UV light. The lost activities were recovered by the addition of MK-4 as well as MK-9(4H), a manaquinone from the bacteria.
2. The abilities of different quinones to restore glycerol-P dehydrogenase activity were compared. The order of effectiveness was; MK-9(4H)>>MK-9(2H)_??_MK-6-10>MK-4_??_phylloquinone (vitamin K1)>menadione>>ubiquinone_??_0.
3. The content of menaquinone in the membrane fraction was 4-7nmoles/mg protein, based on measurement of the oxidation-reduction difference spectra. MK-9(4H) was reduced by oxidizable substrates such as glycerol-P and lactate, but not by succinate, and was oxidized by fumarate. On the other hand, cytochrome b was reduced by succinate as well as glycerol-P and lactate, and was oxidized by fumarate.
4. After irradiation with near-UV light, cytochrome b was not reduced by glycerol-P and NADH, as it had been before, while reduction by lactate and succinate occurred as before.
5. Based on these observations, a scheme including MK-9(4H) is presented for the electron transfer system of P. arabinosum.
