Abstract
A D-galacturonic acid reductase and the corresponding gene were identified from the mold Hypocrea jecorina (Trichoderma reesei). We hypothesize that the enzyme is part of a fungal D-galacturonic acid catabolic pathway which has not been described previously and which is distinctly different from the bacterial pathway. H. jecorina grown on D-galacturonic acid exhibits an NADPH-dependent D-galacturonic acid reductase activity. This activity is absent when the mold is grown on other carbon sources. The D-galacturonic acid reductase was purified, and tryptic digests of the purified protein were sequenced. The open reading frame of the corresponding gene was then cloned from a cDNA library. The open reading frame was functionally expressed in the yeast Saccharomyces cerevisiae. A histidine-tagged protein was purified, and the enzyme kinetics were characterized. The enzyme converts in a reversible reaction from D-galacturonic acid and NADPH to L-galactonic acid and NADP. The enzyme also exhibits activity with D-glucuronic acid and DL-glyceraldehyde.
Original language | English |
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Pages (from-to) | 11234-11240 |
Number of pages | 7 |
Journal | Biochemistry |
Volume | 44 |
Issue number | 33 |
DOIs | |
Publication status | Published - 23 Aug 2005 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Bacteria
- carbon
- cloning
- DNA
- genes
- Yeast
- Hypocrea jecorina
- Saccharomyces cerevisiae