Lee K, Gibson D T
Department of Microbiology, University of Iowa, Iowa City 52242, USA.
Appl Environ Microbiol. 1996 Sep;62(9):3101-6. doi: 10.1128/aem.62.9.3101-3106.1996.
Purified naphthalene dioxygenase (NDO) from Pseudomonas sp. strain NCIB 9816-4 oxidized toluene to benzyl alcohol and benzaldehyde by reactions involving benzylic monooxygenation and dioxygen-dependent alcohol oxidation, respectively. Xylene and nitrotoluene isomers were also oxidized to substituted benzyl alcohol and benzaldehyde derivatives. NDO oxidized ethylbenzene sequentially through (S)-1-phenethyl alcohol (77% enantiomeric excess) and acetophenone to 2-hydroxyacetophenone. In addition, NDO also oxidized ethylbenzene through styrene to (R)-1-phenyl-1,2-ethanediol (74% enantiomeric excess) by reactions involving desaturation and dihydroxylation, respectively. Isotope experiments with 18O2, H2 18O, and D2O suggest that 1-phenethyl alcohol is oxidized to acetophenone by a minor reaction involving desaturation followed by tautomerization. The major reaction in the conversion of 1-phenethyl alcohol and benzyl alcohol to acetophenone and benzaldehyde, respectively, probably involves monohydroxylation to form a gem-diol intermediate which stereospecifically loses the incoming hydroxyl group to leave the carbonyl product. These results are compared with similar reactions catalyzed by cytochrome P-450.
从假单胞菌属菌株NCIB 9816-4中纯化得到的萘双加氧酶（NDO），通过分别涉及苄基单加氧和双氧依赖性醇氧化的反应，将甲苯氧化为苯甲醇和苯甲醛。二甲苯和硝基甲苯异构体也被氧化为取代的苯甲醇和苯甲醛衍生物。NDO依次将乙苯氧化为（S）-1-苯乙醇（对映体过量77%）、苯乙酮，最终生成2-羟基苯乙酮。此外，NDO还通过将乙苯氧化为苯乙烯，再分别通过去饱和反应和二羟基化反应，将其氧化为（R）-1-苯基-1,2-乙二醇（对映体过量74%）。用18O2、H2 18O和D2O进行的同位素实验表明，1-苯乙醇通过一个涉及去饱和反应随后互变异构的次要反应被氧化为苯乙酮。1-苯乙醇和苯甲醇分别转化为苯乙酮和苯甲醛的主要反应，可能涉及单羟基化反应形成偕二醇中间体，该中间体立体选择性地失去引入的羟基，生成羰基产物。将这些结果与细胞色素P-450催化的类似反应进行了比较。
