Staatskultur in Deutschland

Unique sugar metabolism and novel enzymes of hyperthermophilic archaea

“…In the sugar catabolic pathway of P. furiosus , maltose and cellobiose are first transported into the cell, where they are hydrolyzed to glucose by cytoplasmic α‐glucosidase7 and β‐glucosidase,8,9 respectively. Until the early 1990s, the glucose was believed to be further degraded by a novel nonphosphorylated type of Entner‐Doudoroff pathway called pyroglycolysis 10, 11. However, by means of labeling experiments with [1‐13C] glucose, Kengen and colleagues12 identified [2‐13C] acetate and [3‐13C] alanine as the products.…”

“…1, (4)]. However, the activities of these two enzymes in maltose‐grown cells of P. furiosus were found to be very low when assayed in the glycolytic direction 10–12. Because the specific activities of both enzymes were not sufficiently high to envisage a major catabolic role, it was still unclear at that time how an Embden‐Meyerhof pathway could function in this organism.…”

“…During glycolysis in P. furiosus , expression of the gene encoding GAPOR was induced, whereas the activity of GAPDH was repressed 20. On the other hand, the specific activities of GAPDH and PGK have been reported to increase dramatically in pyruvate‐growing cells of P. furiosus 21. This suggests that both GAPDH and PGK mainly function in gluconeogenesis rather than glycolysis.…”

“…P. furiosus is known to have the ability to utilize pyruvate as a sole energy source;22 pyruvate is metabolized to acetate and CO 2 via acetyl‐CoA. Two novel enzymes, pyruvate : ferredoxin oxidoreductase (POR) [Fig.…”