Characterization of Type IV Carboxylate Reductases (CARs) for Whole Cell‐Mediated Preparation of 3‐Hydroxytyrosol
| Autor: | Margit Winkler, Susanne Fritsche, Melissa Horvat, Robert Kourist |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
antioxidant
Antioxidant Bicine medicine.medical_treatment Carboxylic acid reduction 010402 general chemistry 01 natural sciences Catalysis Inorganic Chemistry chemistry.chemical_compound medicine Organic chemistry carboxylate reductase (CAR) Carboxylate Physical and Theoretical Chemistry Trametes versicolor chemistry.chemical_classification in vivo biotransformation Full Paper biology 010405 organic chemistry Organic Chemistry Substrate (chemistry) Full Papers biology.organism_classification 0104 chemical sciences Enzyme chemistry Hydroxytyrosol carboxylic acid |
| Zdroj: | Chemcatchem |
| ISSN: | 1867-3899 1867-3880 |
| DOI: | 10.1002/cctc.201900333 |
| Popis: | Fragrance and flavor industries could not imagine business without aldehydes. Processes for their commercial production raise environmental and ecological concerns. The chemical reduction of organic acids to aldehydes is challenging. To fulfill the demand of a mild and selective reduction of carboxylic acids to aldehydes, carboxylic acid reductases (CARs) are gaining importance. We identified two new subtype IV fungal CARs from Dichomitus squalens CAR (DsCAR) and Trametes versicolor CAR (Tv2CAR) in addition to literature known Trametes versicolor CAR (TvCAR). Expression levels were improved by the co‐expression of GroEL‐GroES with either the trigger factor or the DnaJ‐DnaK‐GrpE system. Investigation of the substrate scope of the three enzymes revealed overlapping substrate‐specificities. Tv2CAR and DsCAR showed a preferred pH range of 7.0 to 8.0 in bicine buffer. TvCAR showed highest activity at pH 6.5 to 7.5 in MES buffer and slightly reduced activity at pH 6.0 or 8.0. TvCAR appeared to tolerate a wider pH range without significant loss of activity. Type IV fungal CARs optimal temperature was in the range of 25–35 °C. TvCAR showed a melting temperature (Tm) of 55 °C indicating higher stability compared to type III and the other type IV fungal CARs (Tm 51–52 °C). Finally, TvCAR was used as the key enzyme for the bioreduction of 3,4‐dihydroxyphenylacetic acid to the antioxidant 3‐hydroxytyrosol (3‐HT) and gave 58 mM of 3‐HT after 24 h, which correlates to a productivity of 0.37 g L−1 h−1. Expanding the toolbox: Fragrance and flavor industries could not imagine business without aldehydes. Mild and selective reduction of carboxylic acids to aldehydes is achieved with new carboxylic acid reductase enzymes (CARs). |
| Databáze: | OpenAIRE |
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