Mowshowitz S, Englard S, Avigad G
J Bacteriol. 1974 Aug;119(2):363-70. doi: 10.1128/jb.119.2.363-370.1974.
A mutant of Gluconobacter cerinus var. ammoniacus, IFO 3267, has been isolated which is deficient with respect to fructose 5-dehydrogenase, the enzyme catalyzing the oxidation of d-fructose to 5-keto-d-fructose (5 KF). Growth of this mutant on fructose as the sole carbon source was impaired unless the culture medium was supplemented with 5 KF. Significant randomization of the 1 and 6 positions of fructose has been reported previously for the wild-type organism during growth on this ketohexose. The pattern of (3)H incorporation into the C5 position of ribonucleic acid-ribose when the mutant was grown on [1-(3)H]fructose and [6-(3)H]fructose in the presence of 5 KF indicated that such randomization did not occur in this variant. The randomization observed in the wild type is, therefore, a consequence of the partial oxidation of fructose to the symmetrical 5 KF intermediate prior to its conversion to pentose. When the mutant was grown on [1-(3)H]fructose in the presence of unlabeled 5 KF, [5-(3)H]fructose appeared in the culture medium. Thus, 5 KF served as the oxidant for the nicotinamide adenine dinucleotide phosphate, reduced form, generated during growth on fructose.
已分离出一种变异的产氨葡萄糖杆菌（Gluconobacter cerinus var. ammoniacus）IFO 3267，它缺乏果糖5-脱氢酶，该酶催化D-果糖氧化为5-酮-D-果糖（5KF）。除非在培养基中添加5KF，否则该突变体在以果糖作为唯一碳源的情况下生长会受到损害。先前已有报道，野生型生物体在以这种己酮糖为碳源生长时，果糖的1位和6位会发生显著的随机化。当突变体在5KF存在的情况下于[1-(3)H]果糖和[6-(3)H]果糖上生长时，(3)H掺入核糖核酸-核糖C5位置的模式表明，这种随机化在该变体中并未发生。因此，在野生型中观察到的随机化是果糖在转化为戊糖之前部分氧化为对称的5KF中间体的结果。当突变体在未标记的5KF存在的情况下于[1-(3)H]果糖上生长时，[5-(3)H]果糖出现在培养基中。因此，5KF作为在果糖上生长期间产生的还原型烟酰胺腺嘌呤二核苷酸磷酸的氧化剂。
