1994 Fiscal Year Final Research Report Summary
Modification of Enzyme Activity and Applications to Peptide Synthesis and Optical Resolution
| Project/Area Number |
04453093
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Synthetic chemistry
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| Research Institution | University of Tsukuba |
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Principal Investigator |
KISE Hideo University of Tsukuba Institute of Materials Science Professor, 物質工学系, 教授 (20013170)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Protease / Peptide Synthesis / Ester Synthesis / Amino acid / Organic solvent / Optical resolution / Fluorescence spectra |
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| Research Abstract |
It has been known that enzymes can retain catalytic activity in organic solvents in the presence of small amounts of water for hydration of the enzymes. In this work, the change in activity and specificity of enzymes in aqueous-organic media was investigated aiming at the development of new applications of enzyme catalysis for synthetic purposes. The modification of enzyme structure by organic solvents was also the subject of the present investigation. The results obtained are summarized as follows :
1) The catalytic activity of proteases was significantly enhanced by amides, amines, and metal ions for the synthesis of esters and peptides in organic solvents. The structure- and concentration-dependency of enzyme catalysis were elucidated, and the results were discussed in terms of enzyme-additive interactions.
2) The structural changes of proteases in organic solvents were detected by fluorescence spectroscopy, and a quantitative relationship was established between the change of emission wavelength and catalytic activity. The results were supported by study of fluorescence quenching, which clearly indicated the changes of direct interaction of tryptophan residues with the quenchers.
3) The reduction of carbonyl compounds was investigated by horse liver alcohol dehydrogenase (HLADH) under aqueous-organic two-phase conditions. The effects of organic solvent on activity and specificity of HLADH were elucidated, and an efficient reaction system was constructed with immobilized HLADH for cyclohexanone reduction with NADH regeneration.
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