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Gewählte Publikation:

Kaswurm, V; Pacher, C; Kulbe, KD; Ludwig, R.
(2012): 2,5-Diketo-gluconic acid reductase from Corynebacterium glutamicum: Characterization of stability, catalytic properties and inhibition mechanism for use in vitamin C synthesis
PROCESS BIOCHEM. 2012; 47(12): 2012-2019. FullText FullText_BOKU

2,5-Diketo-D-gluconic acid (2,5-DKG) reductase is an NADPH-dependent, monomeric aldo-keto reductase (AKR) which catalyzes the reduction of 2,5-DKG to 2-keto-L-gulonic acid (2-KLG) - the immediate precursor of vitamin C. The reaction catalyzed by 2,5-DKG reductase is attractive to bypass several chemical steps and produce vitamin C biocatalytically. In a screening of 22 bacterial strains, nine 2,5-DKG reductase producing bacterial strains were found. The gene of Corynebacterium glutamicum 2,5-DKG reductase was cloned and overexpressed in Escherichia coli. By batch fermentation 409 mg L-1 of 2,5-DKG reductase with a C-terminal His(6)-tag were obtained. The purified 2,5-DKG reductase was characterized in detail. The enzyme is most active in a pH range from 5.0 to 8.0 and its stability is high at temperatures below 35 degrees C. Catalytic constants for 2,5-DKG and NADPH were determined and a weak inhibition by the product 2-KLG was found. 2,5-DKG reductase activity is strongly inhibited by the common process ions Mg2+, Ca2+, SO43- and Cl-, which suggests that these should be avoided in the process. The inhibition mechanism for Cl- was elucidated. It is a competitive inhibitor with respect to NADPH and a noncompetitive inhibitior with respect to 2,5-DKG. (C) 2012 Elsevier Ltd. All rights reserved.
Autor/innen der BOKU Wien:
Kulbe Klaus Dieter
Ludwig Roland
BOKU Gendermonitor:

Find related publications in this database (Keywords)
Ascorbic acid
2,5-Diketo-gluconic acid reductase
2-Keto-L-gulonic acid
Corynebacterium glutamicum

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