Abstract
D-galactose is phosphorylated, 2) the oxidative pathway which starts by an extracellular galactose oxidase reaction, and 3) a recently proposed oxido-reductive pathway which resembles the pathway for L-arabinose catabolism. It has been suggested in T. reesei and A. nidulans the oxido-reductive D-galactose pathway employs the enzymes from the L-arabinose pathway. It starts with the conversion of D-galactose to D-galactitol, probably carried by the xylose/arabinose reductase. The second step is catalyzed by L-arabitol dehydrogenase and the product of the reaction is an unusual sugar L-xylo-3-hexulose. We have identified the L-xylulose reductase possesses the activity
with this intermediate which is converted to D-sorbitol. Finally, D-sorbitol is oxidized to D-fructose, which enters glycolysis. We have studied the pathway in A. niger and uncovered a more complex picture. Apart from showing the possible involvement of the L-arabinose pathway enzymes, we identified two dehydrogenases specifically induced on D-galactose, suggesting that A. niger might have specific genes for catabolism of D-galactose rather than using metabolic crosstalk suggested for T. reesei and A. nidulans.
| Original language | English |
|---|---|
| Title of host publication | 26th Fungal Genetics Conference |
| Subtitle of host publication | Program and Abstracts |
| Publication status | Published - 2011 |
| MoE publication type | Not Eligible |
| Event | 26th Fungal Genetics Conference - Asilomar, United States Duration: 15 Mar 2011 → 20 Mar 2011 |
Publication series
| Series | Fungal Genetics Reports |
|---|---|
| Number | Supplement |
| Volume | 58 |
Conference
| Conference | 26th Fungal Genetics Conference |
|---|---|
| Country | United States |
| City | Asilomar |
| Period | 15/03/11 → 20/03/11 |
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Oxido-reductive metabolism of L-arabinose and D-galactose in filamentous fungi: Metabolic crosstalk versus specific enzymes. / Mojzita, Dominik (Corresponding author); Koivistoinen, Outi; Vuoristo, Kiira; Ruohonen, Laura; Penttilä, Merja; Richard, Peter.
26th Fungal Genetics Conference: Program and Abstracts. 2011. 328 (Fungal Genetics Reports; No. Supplement, Vol. 58).Research output: Chapter in Book/Report/Conference proceeding › Conference abstract in proceedings › Scientific
TY - CHAP
T1 - Oxido-reductive metabolism of L-arabinose and D-galactose in filamentous fungi: Metabolic crosstalk versus specific enzymes
AU - Mojzita, Dominik
AU - Koivistoinen, Outi
AU - Vuoristo, Kiira
AU - Ruohonen, Laura
AU - Penttilä, Merja
AU - Richard, Peter
N1 - CA2: TK402 CA2: TK400
PY - 2011
Y1 - 2011
N2 - L-arabinose, the second most abundant pentose sugar, is used as a carbon source by a variety of microorganisms living on decaying plant material. Fungal microorganisms catabolize L-arabinose through an oxido-reductive pathway. We have identified two missing links in the pathway, L-arabinose and L-xylulose reductases in A.niger. D-galactose is a relatively rare hexose sugar in the plant cell wall mainly found in galactoglucomannan. There are three pathways indentified in fungi for D-galactose degradation; 1) the Leloir pathway in whichD-galactose is phosphorylated, 2) the oxidative pathway which starts by an extracellular galactose oxidase reaction, and 3) a recently proposed oxido-reductive pathway which resembles the pathway for L-arabinose catabolism. It has been suggested in T. reesei and A. nidulans the oxido-reductive D-galactose pathway employs the enzymes from the L-arabinose pathway. It starts with the conversion of D-galactose to D-galactitol, probably carried by the xylose/arabinose reductase. The second step is catalyzed by L-arabitol dehydrogenase and the product of the reaction is an unusual sugar L-xylo-3-hexulose. We have identified the L-xylulose reductase possesses the activitywith this intermediate which is converted to D-sorbitol. Finally, D-sorbitol is oxidized to D-fructose, which enters glycolysis. We have studied the pathway in A. niger and uncovered a more complex picture. Apart from showing the possible involvement of the L-arabinose pathway enzymes, we identified two dehydrogenases specifically induced on D-galactose, suggesting that A. niger might have specific genes for catabolism of D-galactose rather than using metabolic crosstalk suggested for T. reesei and A. nidulans.
AB - L-arabinose, the second most abundant pentose sugar, is used as a carbon source by a variety of microorganisms living on decaying plant material. Fungal microorganisms catabolize L-arabinose through an oxido-reductive pathway. We have identified two missing links in the pathway, L-arabinose and L-xylulose reductases in A.niger. D-galactose is a relatively rare hexose sugar in the plant cell wall mainly found in galactoglucomannan. There are three pathways indentified in fungi for D-galactose degradation; 1) the Leloir pathway in whichD-galactose is phosphorylated, 2) the oxidative pathway which starts by an extracellular galactose oxidase reaction, and 3) a recently proposed oxido-reductive pathway which resembles the pathway for L-arabinose catabolism. It has been suggested in T. reesei and A. nidulans the oxido-reductive D-galactose pathway employs the enzymes from the L-arabinose pathway. It starts with the conversion of D-galactose to D-galactitol, probably carried by the xylose/arabinose reductase. The second step is catalyzed by L-arabitol dehydrogenase and the product of the reaction is an unusual sugar L-xylo-3-hexulose. We have identified the L-xylulose reductase possesses the activitywith this intermediate which is converted to D-sorbitol. Finally, D-sorbitol is oxidized to D-fructose, which enters glycolysis. We have studied the pathway in A. niger and uncovered a more complex picture. Apart from showing the possible involvement of the L-arabinose pathway enzymes, we identified two dehydrogenases specifically induced on D-galactose, suggesting that A. niger might have specific genes for catabolism of D-galactose rather than using metabolic crosstalk suggested for T. reesei and A. nidulans.
M3 - Conference abstract in proceedings
T3 - Fungal Genetics Reports
BT - 26th Fungal Genetics Conference
ER -