Isolation and characterization of a novel D-amidase from Variovorax paradoxus
Research output: Contribution to journal › Research article › Contributed › peer-review
Contributors
Abstract
Using racemic tert-leucine amide as sole nitrogen source in minimal medium, 162 strains were isolated by enrichment techniques and shown to contain amidase activity. Among these isolates three D-amidase producers were found and identified as Variovorax paradoxus (two strains) and Klebsiella spec. The D-amidase from Variovorax paradoxus was purified to homogeneity by three chromatographic steps. With D,L-Tle-amide as substrate Michaelis-Menten kinetics were observed with a KM of 0.74 mM, a KI of 640 mM and a Vmax of 1.4 U/mg. The amidase has a broad pH-optimum between 7 and 9.5 and a temperature optimum at 47 ± 49 °C. The amidase hydrolyzed amino acid amides as well as carboxamides and 2-hydroxy acid amides. The stereoselectivity of the reaction was variable, however. Hydrolyzing D,L-Tle-amide the enantiomeric ratio E was > 200 resulting in D-Tle with an ee of >99% and up to 47% conversion. Similar results were obtained with D,L-Leu-amide and D,L-Val-amide while D,L-Phe-amide was hydrolyzed with an enantiomeric ratio E of only 5.
Details
Original language | English |
---|---|
Pages (from-to) | 965-973 |
Journal | Advanced synthesis & catalysis |
Volume | 2002 |
Issue number | 344 |
Publication status | Published - 2002 |
Peer-reviewed | Yes |
Externally published | Yes |
External IDs
Scopus | 0346007406 |
---|---|
ORCID | /0000-0002-2912-546X/work/171552003 |
Keywords
Keywords
- Biokatalyse, Amidase, Aminosäure, Screening