化学学报 ›› 2013, Vol. 71 ›› Issue (07): 1064-1070.DOI: 10.6023/A13030249 上一篇    下一篇

研究论文

光动不对称加氢制备高光学纯度(S)-4-三甲基硅基-3-丁炔-2-醇的研究

胡锐, 张承平, 裴志胜   

  1. 琼州学院理工学院 三亚 572022
  • 收稿日期:2013-03-07 出版日期:2013-07-14 发布日期:2013-04-10
  • 通讯作者: 胡锐, E-mail: hr45220048@gmail.com; Tel.: 15120716578 E-mail:hr45220048@gmail.com
  • 基金资助:

    项目受海南省高等学校科学研究项目(No. HJKJ2011-38)资助.

Mechanistic Investigation of Light-induced Asymmetric Hydrogenation of TMSBO by Anoxygenic Photosynthetic Bacteria

Hu Rui, Zhang Chengping, Pei Zhisheng   

  1. Institute of Technology, Qiongzhou University, Sanya 572022
  • Received:2013-03-07 Online:2013-07-14 Published:2013-04-10
  • Supported by:

    Project supported by the Higher School Science Research Project of Hainan Province (No. HJKJ2011-38).

高光学纯度的(S)-4-三甲基硅基-3-丁炔-2-醇是一种重要的药物手性中间体. 以4-三甲基硅基-3-丁炔-2-酮作为模型底物, 从51株不产氧光合细菌中筛选出一株高效目标功能菌株Thiocapsa roseopersicina SJH001作为生物催化剂进行光动不对称加氢催化反应, 在未经优化的反应条件下, 其产物(S)-TMSBL的ee值高于99%, 产率高达80%以上. 从Thiocapsa roseopersicina SJH001分离得到了新的NADPH依赖型氧化还原酶[(S)-氧化还原酶和(R)-氧化还原酶]. 粗酶经硫酸铵分级沉淀、Q-sepharose阴离子交换层析、Sephacryl S-200丙烯葡聚糖凝胶过滤层析后在SDS-PAGE上显示为单一条带, 其酶蛋白的相对分子质量为44.5 kDa, 相对酶活为449.8 U/mg, 高于文献报道的同类具有对映体选择性氧化还原酶. 通过比较光照强度、pH值、反应前对菌体细胞热预处理、底物浓度对Thiocapsa roseopersicina SJH001胞内氧化还原酶的活性和构型产生的影响, 进一步在分子水平阐明了光动不对称加氢催化反应的机理.

关键词: 光动不对称加氢, (S)-氧化还原酶, (R)-氧化还原酶, 4-三甲基硅基-3-丁炔-2-酮, (S)-4-三甲基硅基-3-丁炔-2-醇

Enantiomerically pure organosilicon compounds 3-butyn-2-ol not only play an important part in asymmetric synthesis and functional materials, but also many of them are bioactive and can be applied as silicon-containing drugs, such as (S)-3-butyn-2-ol or its derivative (S)-4-(trimethylsilyl)-3-butyn-2-ol {(S)-TMSBL} is a crucial intermediate for the synthesis of 5-lipoxygenase inhibitors. The anoxygenic phototrophic bacteria capable of reducing TMSBO to the (S)-TMSBL with high yield and ee were screened, using absolute configuration, stereoselectivity, and yield as benchmarks. 51 anoxygenic phototrophic bacteria strains were tested. We, for the first time, describe the efficient synthesis of enantiopure (S)-TMSBL, which is a crucial intermediate for the synthesis of 5-lipoxygenase inhibitors through the light-controlled asymmetric hydrogenation of TMSBO by photosynthetic bacteria Thiocapsa roseopersicina SJH001, which is a newly isolated photosynthetic bacteria strain that has the capacity to capture light energy and to generate NADPH through photosynthetic electron-transfer reactions. No oxygen or other metabolic intermediates were used, which make it easy to keep higher activities of redoxase and to separate reduced product, the reducing power of NADPH generated through photosynthesis also can be used in the reduction of exogenous substrates. A novel NADPH dependent carbonyl reductase was separated from Thiocapsa roseopersicina SJH001. The enzyme gave a single band on SDS-PAGE, which was purified through ammonium sulfate, Q-sepharose anion exchange column, gel filtration chromatography on a Superdex 200 column from cell-free extract. The molecular mass of the enzyme was about 44.5 kDa, relative enzyme activity was 449.8 U/mg, which is comparable to the previously reported carbonyl reductases from other sources. These results suggested that pH, light intensity, heat-treat biocatalysis with different temperature, substrate concentration has great influence on the enzyme activity and configuration of carbonyl reductase ((S)-carbonyl reductase and (R)-carbonyl reductase) from Thiocapsa roseopersicina SJH001. We propose a probable mechanism for light-induced asymmetric hydrogenation of TMSBO to produce (S)-TMSBL by anoxygenic photosynthetic bacteria.

Key words: light-induced asymmetric hydrogenation, (S)-carbonyl reductase (R)-carbonyl reductase, 4-(trimethylsilyl)-3-butyn-2-one, (S)-4-(trimethylsilyl)-3-butyn-2-ol