Boronat A, Caballero E, Aguilar J
J Bacteriol. 1983 Jan;153(1):134-9. doi: 10.1128/jb.153.1.134-139.1983.
Spontaneous mutants of Escherichia coli able to grow on ethylene glycol as a sole source of carbon and energy were obtained from mutants that could grow on propylene glycol. Attempts to obtain ethylene glycol-utilizing mutants from wild-type E. coli were unsuccessful. The two major characteristics of the ethylene glycol-utilizing mutants were (i) increased activities of propanediol oxidoreductase, an enzyme present in the parental strain (a propylene glycol-positive strain), which also converted ethylene glycol into glycolaldehyde; and (ii) constitutive synthesis of high activities of glycolaldehyde dehydrogenase, which converted glycolaldehyde to glycolate. Glycolate was metabolized via the glycolate pathway, which was present in the wild-type cells; this was indicated by the induction in ethylene glycol-grown cells of glycolate oxidase, the first enzyme in the pathway. Glycolaldehyde dehydrogenase was partially characterized as an enzyme of this new metabolic pathway in E. coli, and glycolate was identified as the product of the reaction. This enzyme used NAD and NADP as coenzymes, although the NADP-dependent activity was about 10 times lower than the NAD-dependent activity. Uptake of [14C]ethylene glycol was dependent on the presence of the enzymes capable of metabolism of ethylene glycol. Glycolaldehyde and glycolate were identified as intermediate metabolites in the pathway.
能以乙二醇作为唯一碳源和能源生长的大肠杆菌自发突变体是从能在丙二醇上生长的突变体中获得的。从野生型大肠杆菌中获得利用乙二醇的突变体的尝试未成功。利用乙二醇的突变体的两个主要特征是：（i）丙二醇氧化还原酶的活性增加，该酶存在于亲本菌株（丙二醇阳性菌株）中，也能将乙二醇转化为乙醇醛；（ii）组成型合成高活性的乙醇醛脱氢酶，该酶将乙醇醛转化为乙醇酸。乙醇酸通过野生型细胞中存在的乙醇酸途径进行代谢；这一点由在以乙二醇为碳源生长的细胞中乙醇酸氧化酶（该途径的第一种酶）的诱导所表明。乙醇醛脱氢酶被部分鉴定为大肠杆菌中这条新代谢途径的一种酶，并且乙醇酸被鉴定为该反应的产物。这种酶使用NAD和NADP作为辅酶，尽管依赖NADP的活性比依赖NAD的活性低约10倍。[¹⁴C]乙二醇的摄取取决于能够代谢乙二醇的酶的存在。乙醇醛和乙醇酸被鉴定为该途径中的中间代谢物。
