Glyceraldehyde-3-phosphate ferredoxin oxidoreductase, a novel tungsten-containing enzyme with a potential glycolytic role in the hyperthermophilic archaeon Pyrococcus furiosus.
The archaeon Pyrococcus furiosus grows optimally at 100 degrees C by the fermentation of carbohydrates to yield acetate, CO2, and H2. Cell-free extracts contain very low activity of the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase, but extremely high activity of glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR). GAPOR was purified under strictly anaerobic conditions. It is a monomeric, O2-sensitive protein of M(r) approximately 63,000 which contains pterin and approximately 1 tungsten and 6 iron atoms per molecule. The enzyme oxidized glyceraldehyde-3-phosphate (Km 28 microM) to 3-phosphoglycerate and reduced P. furiosus ferredoxin (Km 6 microM), but it did not oxidize formaldehyde, acetaldehyde, glyceraldehyde, benzaldehyde, glucose, glucose 6-phosphate, or glyoxylate, nor did it use NAD(P) as an electron acceptor. It is proposed that GAPOR has a glycolytic role and functions in place of glyceraldehyde-3-phosphate dehydrogenase and possibly phosphoglycerate kinase.
Mukund
S
S
Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA.
Adams
M W
MW
D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology*; D002384:Catalysis; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006019:Glycolysis; D008969:Molecular Sequence Data; D014414:Tungsten
D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; C093132:glyceraldehyde-3-phosphate ferredoxin oxidoreductase; D014414:Tungsten