Waxmonoester fermentation in Euglena gracilis T. Factors favouring the synthesis of odd-numbered fatty acids and alcohols
Waxmonoester fermentation in Euglena gracilis T. Factors favouring the synthesis of odd-numbered fatty acids and alcohols
复制标题
眼虫蜡单酯发酵。有利于合成奇数脂肪酸和醇的因素
作者：
T. Schneider;A. Betz
在自养的纤细裸藻中，蜡单酯的发酵是在黑暗中进行的，以牺牲内源副尼龙为代价。在严格的厌氧条件下，随着氧分压的降低和耗氧率的降低，奇数脂肪酸和醇的比例增加到近1：1的摩尔比。标记为14CO2的琥珀酸和丙酸被结合到奇数脂肪酸和醇中的速度是偶数链的11到33倍。电子流动抑制剂鱼藤酮总体上减少了蜡酯的形成，但特别是二氧化碳固定和奇数链的合成，而不阻碍厌氧碳水化合物的分解。这些发现表明丙酰辅酶A是合成奇数链的中间体。从能量学的角度讨论了其在甲基丙二酰辅酶A途径中的可能合成。
Waxmonoester fermentation at the expense of endogenous paramylon was followed in the dark in autotrophically grown Euglena gracilis. With reduced oxygen tension and decreasing O2-consumption rates the proportion of odd-numbered fatty acids and alcohols increased up to a molar ratio of nearly 1:1 under strictly anaerobic conditions. Labelled 14CO2, succinate and propionate were incorporated into odd-numbered fatty acids and alcohols 11 to 33 times faster than in even-numbered chains. The electron-flow inhibitor rotenone diminished waxester formation in total, but especially CO2 fixation and the synthesis of odd-numbered chains, without impeding anaerobic carbohydrate breakdown. These findings are indicative for propionyl-CoA as an intermediate in the synthesis of odd-numbered chains. Its probable synthesis in the methylmalonyl-CoA pathway is discussed with regard to energetics.