Continuous Synthesis of a Tripeptide by Successive Condensation and Transesterification Catalyzed by Two Immobilized Proteinases in Organic Solvent(Microbiology & Fermentation Industry)

概要

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The tripeptide Z-GlyPheLeuNH_2 was continuously synthesized in a high yield from three amino acid derivatives, Z-Gly, PheOMe, and LeuNH_2, by immobilized thermolysin (IMT) and immobilized a-chymotrypsin (IMC) in an organic solvent, ethyl acetate. The optimal conditions for the synthesis of Z-GlyPheOMe were established theoretically. The yield of Z-GlyPheOMe with IMT in ethyl acetate saturated with buffer was more than 88% after continuous synthesis for 116hr. The optimal conditions for the synthesis of Z-GlyPheLeuNH_2 from Z-GlyPheOMe and LeuNH_2 by IMC through transesterifkation was established in batch reaction experiments. When the concentration of water in the reaction solution was 17-20 μl/ml, the activity of IMC was highest. The equilibrium between the water concentration in the reaction solution and that in the resin used for enzyme immobilization depended on the resin and was not affected by the presence of the enzyme immobilized. Z-GlyPheLeuNH_2 was synthesized from Z-GlyPheOMe and LeuNH_2 with a yield of 100%, by continuous reaction for 160 hr. The reactor for synthesis of this tripeptide was efficient and stable because of the use of transesterifkation and the choice of an appropriate organic solvent. The series plug-flow reactor was successfully operated for 220 hr with a yield of more than 80 %. The residual activity of IMT was 94%, and that of IMC was 100%.
社団法人日本農芸化学会の論文
1990-06-23