1. Purification and characterization of a lactonase from erwinia cypripedii 314b that hydrolyzes ( s)-5-oxo-2-tetrahydrofurancarboxylic acid.
Kazuya Mochizuki. Arch Microbiol. 2003 Dec; 180(6): 490-3. DOI: 10.1007/s00203-003-0597-5. PMID: 14576976.
A bacterium, strain 314B, able to assimilate ( S)-5-oxo-2-tetrahydrofurancarboxylic acid was isolated from soil and identified as Erwinia cypripedii. A lactonase hydrolyzing ( S)-5-oxo-2-tetrahydrofurancarboxylic acid to l-alpha-hydroxyglutaric acid was purified 63-fold with 2% recovery from crude extracts of this bacterium to homogeneity as judged by SDS-PAGE. The molecular masses estimated by SDS-PAGE and gel filtration were 41 kDa and 79 kDa, respectively. The maximum activity was observed at pH 6.5-7.5 and 35-45 degrees C. The enzyme showed lower activity toward dl-2-oxotetrahydrofuran-4,5-dicarboxylic acid, but did not act on ( R)-5-oxo-2-tetrahydrofurancarboxylic acid and other natural and synthetic lactones tested.
2. Purification and characterization of a lactonase from burkholderia sp. R-711, That hydrolyzes (r)-5-oxo-2-tetrahydrofurancarboxylic acid.
K Mochizuki. Arch Microbiol. 2001 Jun; 175(6): 430-4. DOI: 10.1007/s002030100283. PMID: 11491083.
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 degrees C. 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.