Purification and characterization of a lactonase from Burkholderia sp R-711, that hydrolyzes (R)-5-oxo-2-tetrahydrofurancarboxylic acid

摘要

A lactonase hydrolyzing (R)-5-oxo-2-tetrahydrofurancarboxylic acid to D-alpha -hydroxyglutaric acid was purified 170-fold with 2% recovery to near homogeneity from crude extracts of Burkholderia sp. R-711, which had been isolated as a bacterium able to assimilate (R)-5-oxo-2-tetrahydrofurancarboxylic acid. The molecular mass was estimated to be 33 kDa by gel filtration. The purified preparation migrated as a single band of molecular mass 38 kDa upon SDS-PAGE. The maximum activity was observed at pH 7.0-8.0 and 35-40 degreesC. The enzyme required no added cofactors or metal ions: the activity was inhibited to 60-100% by SH-blocking reagents, but was not affected by metal-chelating reagents. The enzyme showed lower activity and affinity toward (S)-5-oxo-2-tetrahydrofurancarboxylic acid, but did not act on other natural and synthetic lactones tested. [References: 16]