- 作者: 鄭建業
- 作者服務機構: Department of Chemistry, Chung Yuan Christian University, Chungli, Taiwan 320, R.O.C.
- 中文摘要: The racemization of D-aspartic acid to L-aspartic acid has been successfully performed with a coupled enzyme system at 90 °C and a pH of about 4.0 by the assay of high-performance liquid chromatography. This coupled enzymatic racemization is a successive two-step reaction first induced by D-amino acid oxidase and a subsequent coupled reaction by an aminotransferase clonezyme with the help of coenzyme pyridoxal 5¢-phosphate and cosubstrate L-glutamate. Due to the very high temperature, part of the L-aspartic acid is produced by the thermal effect. In fact the thermal racemization for aspartic acid can proceed from either D- or L-aspartic acid via an intermediate fumaric acid and leads to the formation of D,L-malic acid. The formation of a-oxalacetic acid formed irreversibly from D-aspartic acid with D-amino acid oxidase can induce a side reaction to L-alanine. The thermal effect may also be responsible for the production of D-, and L-alanine.
- 英文摘要: --
- 中文關鍵字: Reaction routes; Thermal and enzymatic racemization; D-Aspartic acid; L-Aspartic acid; High-performance liquid chromatography
- 英文關鍵字: Reaction routes; Thermal and enzymatic racemization; D-Aspartic acid; L-Aspartic acid; High-performance liquid chromatography