Kinetic resolution of α-methylbenzylamine with o-transaminase screened from soil microorganisms: Application of a biphasic system to overcome product inhibition
✍ Scribed by Jong-Shik Shin; Byung-Gee Kim
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 301 KB
- Volume
- 55
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Chiral amines among sole nitrogen source. Optimal carbon and nitrogen them are of great importance for the pharmaceutical and sources for enzyme induction and the properties of Ͷtransaminases were investigated. Ͷ-Transaminase from fine-chemical industries. They are used as intermediates B. thuringiensis JS64 was highly enantioselective (E ϭ and end products in the synthesis of cardiovascular, 75.3) for (S)-enantiomer of Ͱ-MBA and showed remark-
antihypertensive, and antiemetic drugs as well as chiral able stability. However, Ͷ-transaminase showed severe resolving auxiliaries for the preparation of optically pure product inhibition by acetophenone. An aqueous/organic carboxylic acids. Due to the great usefulness and versatwo-phase system was introduced to overcome this problem. Through solvent screening, cyclohexanone and tility of these compounds, many optically active amines ethyl acetate were selected as the best organic phases.
have been used for asymmetric synthesis and chemical
The acetophenone-extracting capacity of the solvent and resolution (Gutman et al., 1992; Kitaguchi et al., 1989).
the biocompatibility of the solvent to the cell were im-We were interested in applying various enzyme sysportant determinants in the reaction rate at high concentrations of Ͱ-MBA. The reaction rate of Ͷ-transaminatems for either the asymmetric synthesis or the resolution was strongly influenced by the volume ratio of ortion of chiral amine compounds. Depending upon the ganic phase to aqueous phase as well as agitation speed reaction mechanism of each enzyme, asymmetric synin the biphasic mixture. Using the optimal volume ratio thesis or/and resolution can be separately designed with (V org : V aq ϭ 1 : 4) in the biphasic system with cyclohexanone, the reaction rate of Ͷ-transaminase under vigorous one enzyme. By and large, we can divide the possible mixing conditions increased ninefold compared with that enzyme systems into two groups based on the reaction in the monophasic aqueous system. At the same optimal media: one working in an aqueous system, and the other conditions, using whole cells, 500 mM Ͱ-MBA could be in an organic solvent system. resolved successfully to above 95% enantiomeric excess Hydrolytic enzymes, such as protease, lipase, and esof (R)-Ͱ-MBA with ca. 51% conversion.