Stereochemistry of an α,β‐elimination reaction by D‐glucosaminate dehydratase

FEBS Letters

Iwamoto, Ryoko³  Sawada, Seiji¹  Imanaga, Yujiro³  Soda, Kenji² 

[1] Department of Chemistry, Kyoto University of Education, Kyoto 612, Japan;Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu 611, Japan;Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630 Japan

关键词: D-Glucosaminate dehydratase;    α;    β-Elimination reaction;    Pyridoxal 5'-phosphate;    Proton NMR analysis;    Stereochemistry;    Agrobacterium radiobacter;   

DOI  :  10.1016/0014-5793(83)80242-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The proton NMR analysis of D-glucosaminate dehydratase reaction in D₂O revealed the incorporation of a deuterium atom at C-3 carbon of the product, 2-keto-3-deoxy-D-gluconate. Based on the chemical shift of C-3 proton of the product and the coupling constant characteristic for the C-3 and C-4 axial-axial coupling in the ²C₅ pyranose conformation, the deuterium is in the pro-S position. Thus, the dehydration of D-glucosaminate by the enzyme proceeds in a retention mode at C-3 carbon. Kinetic parameters show that the rate-determining step is the abstraction of α-proton from the substrate.

【 授权许可】

Unknown