The metabolism of hydrogen by extremely thermophilic bacteria
The novel archaebacterium, Pyrococcus furiosus, grows optimally at 100{degree}C by a fermentative metabolism and produces hydrogen (H{sub 2}). We have shown that this organism appears to ferment glucose and evolve H{sub 2} by a novel pathway. The following metalloenzymes and proteins involved in H{sub 2} metabolism have been purified and characterized: hydrogenase (NiFeS), ferredoxin (FeS), pyruvate ferredoxin oxidoreductase (FeS), and an new enzyme which contains tungsten, glyceraldehyde ferredoxin oxidoreductase (WFeS). A rubredoxin was also purified, and it and the ferredoxin have been sequenced. In addition, a second new enzyme has been identified, glucose ferredoxin oxidoreductase. These represent the first enzymes and proteins to be purified from any organism able to grow optimally above 90{degree}C. All are remarkably thermostable and show maximal catalytic activity >95{degree}C. The ferredoxin has several unique properties and is potentially an extremely thermostable model for the catalytic sites of a variety of mesophilic metalloenzymes. In addition, the FeS-containing enzymes, hydrogenase and pyruvate ferredoxin oxidoreductase, and a ferredoxin, have been purified from the most thermophilic eubacterium currently known, Thermotoga maritima. This organism grows up to 90{degree}C, also by fermentation. The hydrogenases of T. maritima and P. furiosus each have many unique properties in comparison with mesophilic hydrogenases, and both appear to contain new types of metal centers that are specifically adapted to catalyze H{sub 2} production at the extreme temperatures. Hydrogenase activity has also been measured in four other extremely thermophilic organisms, one of which is capable of growth at 120{degree}C. 1 fig.
- Research Organization:
- Georgia Univ., Athens, GA (USA). Dept. of Biochemistry
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- FG09-88ER13901
- OSTI ID:
- 5880290
- Report Number(s):
- DOE/ER/13901-3; ON: DE91011031
- Country of Publication:
- United States
- Language:
- English
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Novel and remarkably thermostable ferredoxin from the hyperthermophilic archaebacterium Pyrococcus furiosus
The metabolism of hydrogen by extremely thermophilic bacteria: Progress report, April 1988--December 1988
Related Subjects
080106* -- Hydrogen-- Production-- Biosynthesis & Photochemical Processes
ALDEHYDES
BACTERIA
BIOCONVERSION
CARBOHYDRATES
DOCUMENT TYPES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
FERMENTATION
FERREDOXIN
GLUCOSE
GROWTH
HEXOSES
HYDROGEN
HYDROGEN PRODUCTION
METABOLISM
METALLOPROTEINS
MICROORGANISMS
MONOSACCHARIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROGRESS REPORT
PROTEINS
SACCHARIDES