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Identification of a D-galacturonate reductase efficiently using NADH as a cofactor
Kaisa E Peltonen1, Peter Richard1
1VTT Technical Research Centre of Finland Ltd., Tietotie 2, 02150 Espoo, Finland.
Biotechnology Reports (Amsterdam, Netherlands)
|June 17, 2022
Summary
Researchers discovered a D-galacturonate reductase (gaa1) that efficiently uses both NADH and NADPH. This enzyme is key for engineering microbes to utilize pectin-rich biomass for biofuel production.
Area of Science:
- Biochemistry
- Enzymology
- Metabolic Engineering
Background:
- D-galacturonate reductases (DRs) catalyze the interconversion of D-galacturonate and L-galactonate using NAD(P)H.
- These enzymes are crucial in fungal pectin catabolism and plant L-ascorbic acid synthesis.
- Naturally occurring DRs typically show higher activity with NADPH than NADH.
Purpose of the Study:
- To identify and characterize novel D-galacturonate reductases with distinct cofactor preferences.
- To explore the potential of these enzymes in biotechnological applications, particularly in pectin utilization.
Main Methods:
- Gene identification and cloning from *Euglena gracilis*.
- Enzyme activity assays using NADH and NADPH as cofactors.
- Bioinformatic analysis of the identified enzyme.
Main Results:
- A gene, *gaa1*, was identified in *E. gracilis*, encoding a D-galacturonate reductase.
- The Gaa1 enzyme exhibited comparable catalytic activity with both NADH and NADPH.
- This contrasts with previously characterized DRs that strongly prefer NADPH.
Conclusions:
- The Gaa1 enzyme represents a novel D-galacturonate reductase with dual cofactor preference.
- Its unique cofactor flexibility makes it a promising candidate for metabolic engineering applications.
- Gaa1 could facilitate the efficient valorization of pectin-rich biomass by microorganisms.
