Department of Biology, Missouri State University, 901 South National Avenue, Springfield, MO 65897, USA.
Appl Microbiol Biotechnol. 2013 Apr;97(8):3475-84. doi: 10.1007/s00253-012-4395-3. Epub 2012 Sep 18.
Two genes encoding recombinant cytosolic oxidoreductases from Gluconobacter oxydans, gox0313 and gox0646, were heterologously expressed in Escherichia coli and the resulting proteins were purified and characterized. GOX0313 was identified as a medium-chain alcohol dehydrogenase, whereas GOX0646 was classified as a ketocarbonyl reductase. GOX0313 had a broad substrate spectrum and oxidized various primary alcohols. However, GOX0313 had a preference for substrate reduction, reducing many aldehydes and α-diketones. In contrast, GOX0646 had a narrow substrate spectrum and reduced α-diketones, preferring short-chain ketocarbonyls. Both enzymes regio- and stereospecifically reduced α-diketones to the corresponding (S)-hydroxy ketone, as shown by NMR. These products are difficult to produce chemically, requiring complicated protecting group chemistry. Furthermore, hydroxy ketones find industrial application in the production of pheromones, fragrances, flavors, and pharmaceuticals. Hence, these enzymes are interesting biocatalysts for the production of enantiomerically pure building blocks that are difficult to prepare chemically.
来自氧化葡萄糖酸杆菌的两个编码重组胞质氧化还原酶的基因，gox0313 和 gox0646，在大肠杆菌中异源表达，得到的蛋白质被纯化并进行了表征。GOX0313 被鉴定为中链醇脱氢酶，而 GOX0646 被归类为酮羰基还原酶。GOX0313 具有广泛的底物谱，可以氧化各种伯醇。然而，GOX0313 更倾向于进行底物还原，还原许多醛和α-二酮。相比之下，GOX0646 具有较窄的底物谱，优先还原α-二酮，更喜欢短链的酮羰基。两种酶均具有区域和立体选择性地将α-二酮还原为相应的（S）-羟基酮，如 NMR 所示。这些产物在化学上难以生产，需要复杂的保护基团化学。此外，羟基酮在生产信息素、香料、风味和药物方面具有工业应用。因此，这些酶是生产难以用化学方法制备的手性纯构建块的有趣生物催化剂。
