权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Expansion of application of biocatalysts by introduction of organic solvents and non-natural substrates

通过引入有机溶剂和非天然底物扩大生物催化剂的应用

基本信息

批准号：
05453111
负责人：
TANAKA Atsuo
金额：
$ 4.8万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

It is important to draw out the latent abilities and expand the use of biocatalysts by introducing unusual conditions such as organic solvents and non-natural substrates. We found in this study that halophenylalanines served as non-natural substrates of thermolysin, and the enantioselective synthesis of non-natural peptides containing halophenylalanines was successfully carried out. These non-natural poptides are expected to have novel physiological activities. Furthermore, we tried the bioconversion of organosilicon compounds which play important roles in organic synthesis, and succeeded in the optical resolution of primary alcohols containing stereogenic silicon atom. It was also demonstrated that the dehydrogenation of primary beta-hydroxysilanes proceeded enantioselectively with only alcohol dehydrogenase (HLADH) and a catalytic amount of NAD^+ due to in-situ NAD^+ regeneration. That is, beta-hydroxysilanes were dehydrogenated by HLADH to beta-carbonylsilanes, which were spontaneously degraded into aldehydes, which served substrates for HLADH to regenerate NAD^+. These results indicated that the application of specific features of organosilicon compounds enabled the construction of the efficient bioconversion systems, being impossible with conventional substrates. In addition, it was found that the use of non-natural acid anhydrides as acyl donors in fed-batch system could avoid the accumulation of water which is a big problem of hydrolasecatalyzed esterification. We were also successful in constructing a novel non-support bioreactor needing no conventional immobilization by introducing organic solvent as unusual condition because biocatalysts are not soluble in organic solvents.

通过引入有机溶剂和非天然底物等非常规条件，发挥生物催化剂的潜力，扩大其应用范围具有重要意义。本研究发现卤代苯丙氨酸是嗜热菌蛋白酶的非天然底物，并成功地进行了含卤代苯丙氨酸的非天然多肽的对映选择性合成。这些非天然的多肽有望具有新的生理活性。此外，我们还尝试了有机硅化合物的生物转化，并成功地对含立体硅原子的伯醇进行了光学拆分。研究还表明，由于NAD^+的原位再生，仅用醇脱氢酶（HLADH）和催化量的NAD^+，伯β-羟基硅烷的脱氢反应对映选择性地进行。也就是说，β-羟基硅烷被HLADH脱氢成β-羰基硅烷，后者自发降解成醛，醛充当HLADH再生NAD^+的底物。这些结果表明，有机硅化合物的特定功能的应用，使有效的生物转化系统的建设，是不可能与传统的基板。另外，在流加反应体系中使用非天然酸酐作为酰基给体，可以避免水解酶催化酯化反应中的水积累问题。由于生物催化剂不溶于有机溶剂，我们还成功地构建了一种新型的非支撑生物反应器，不需要常规的固定化，通过引入有机溶剂作为非常规条件。