St Martin E J, Mortlock R P
J Bacteriol. 1980 Mar;141(3):1157-62. doi: 10.1128/jb.141.3.1157-1162.1980.
A mutant strain of Klebsiella aerogenes was constructed and, when incubated anaerobically with L-fucose and glycerol, synthesized and excreted a novel methyl pentitol, 6-deoxy L-talitol. The mutant was constitutive for the synthesis of L-fucose isomerase but unable to synthesize L-fuculokinase activity. Thus, it could convert the L-fucose to L-fuculose but was incapable of phosphorylating L-fuculose to L-fuculose 1-phosphate. The mutant was also constitutive for the synthesis of ribitol dehydrogenase, and in the presence of sufficient reducing power this latter enzyme catalyzed the reduction of the L-fuculose to 6-deoxy L-talitol. The reducing equivalents required for this reaction were generated by the oxidation of glycerol to dihydroxyacetone with an anaerobic glycerol dehydrogenase. The parent strain of K. aerogenes was unable to utilize the purified 6-deoxy L-talitol as a sole source of carbon and energy for growth; however, mutant could be isolated which had gained this ability. Such mutants were found to be constitutive for the synthesis of ribitol dehydrogenase and were thus capable of oxidizing 6-deoxy L-talitol to L-fuculose. Further metabolism of L-fuculose was shown by mutant analysis to be mediated by the enzymes of the L-fucose catabolic pathway.
构建了产气克雷伯菌的突变株，该突变株在与L-岩藻糖和甘油进行厌氧培养时，合成并分泌了一种新型甲基戊糖醇，即6-脱氧-L-塔罗糖醇。该突变株在L-岩藻糖异构酶的合成上呈组成型，但无法合成L-岩藻糖激酶活性。因此，它可以将L-岩藻糖转化为L-岩藻酮糖，但无法将L-岩藻酮糖磷酸化为L-岩藻酮糖1-磷酸。该突变株在核糖醇脱氢酶的合成上也呈组成型，并且在有足够还原力的情况下，后一种酶催化L-岩藻酮糖还原为6-脱氧-L-塔罗糖醇。该反应所需的还原当量通过厌氧甘油脱氢酶将甘油氧化为二羟基丙酮来产生。产气克雷伯菌的亲本菌株无法利用纯化的6-脱氧-L-塔罗糖醇作为唯一的碳源和能量来源进行生长；然而，可以分离出具有这种能力的突变株。发现这些突变株在核糖醇脱氢酶的合成上呈组成型，因此能够将6-脱氧-L-塔罗糖醇氧化为L-岩藻酮糖。通过突变分析表明，L-岩藻酮糖的进一步代谢是由L-岩藻糖分解代谢途径的酶介导的。
