Pyrococcus furiosus hydrogenase

Hopkins, R.C., Sun, J., Jenney, F.E., Chandrayan, S.K., McTernan, P.M., and Adams, M.W.W. (2011) Homologous expression of a subcomplex of Pyrococcus furiosus hydrogenase that interacts with pyruvate ferredoxin oxidoreductase. PLoS One, 6, e26569. 

Greiner L, Schroder I, Mulle DH, Liese A. Utilization of adsorption effects for the continuous reduction of NADP" " with molecular hydrogen by Pyrococcus furiosus hydrogenase. Green Chem 2003 5 697-700. 

Methods to calculate such charge transfer efficiency of bound enzymes have recently been reported [25], One first calculates a theoretical maximum in current density based on enzyme loading, determined from spectrophotometric measurements (assuming perfect charge transfer efficiency), and then compares the value with the actual measured current density, obtained from direct current (DC) polarization experiments. For example, the direct absorption of Pyrococcus furiosus hydrogenase 1 onto carbon-based electrodes was used as a model redox enzyme system, and Faraday s law was used to calculate the maximum theoretical current density as follows (Equation 12.1) ... 

Ma K, R Weiss, MWW Adams (2000) Characterization of hydrogenase II from the hyperthermophilic archaeon Pyrococcus furiosus and assessment of its role in sulfur reduction. J Bacteriol 182 1864-1871. 

The ability to catalyse the evolution or oxidation of H2 may have been exploited by the earliest life forms as H2 would have been present in the early prebiotic environments. The origins of the proton-dependent chemiosmotic mechanism for ATP synthesis may also reflect the formation of proton gradients created by hydrogenases on either side of the cytoplasmic membrane. In addition, it has been speculated that the coupling of H2 and S metabolisms was also of fundamental importance in the origin of life. These two processes seem intimately coupled in the bifunctional sulfhydrogenase found in Pyrococcus furiosus (a combination of subunits for hydrogenase and sulfite reductase) which can dispose of excess reductant either by the reduction of protons to H2 or S° to H2S (Ma et al. 1993 Pedroni et al. 1995). 

Bryant, F. O. and Adams, M. W. (1989) Characterization of hydrogenase from the hyperther-mophilic archaebacterium, Pyrococcus furiosus. J. Biol. Chem., 264, 5070-9. 

Ma, K., Schicho, R. N., Kelly, R. M. and Adams, M. W. W. (1993) Hydrogenase of the hyper-thermophile Pyrococcus furiosus is an elemental sulfur reductase or sulfhydrogenase Evidence for a sulfur-reducing hydrogenase ancestor. Proc. Natl. Acad. Sci. USA, 90, 5341-4. 

Fig. 3.44 Cofactor recycling using Hydrogenase I from Pyrococcus furiosus.

Hydrogenase purified from the bacterium Pyrococcus furiosus has been combined with the enzymes of the pentose phosphate cycle to produce hydrogen from glucose-6-phosphate and NADP (Woodward et al., 2000). Similar experiments have been made using hydrogenase from Thiocapsa ro-... 

The enzymes produced by these extremophiles, known as extremozymes, can function under extreme conditions. An illustrative list along with an indication of the extreme environments in which they can function is included in Table 20.1 (sources Kushner, 1978 Jones et al., 1983 Huber et al., 1989 Li et al., 1993 Davail et al., 1994 Adams et al., 1995). Enzymes extracted from these microorganisms have been tested for a variety of reactions and optimum temperatures have been found. Examples are enzymes from Pyrococcus furiosus for a- and p glucosidase, a-amylase, protease, and hydrogenase activities (Bryant and Adams, 1989 Costantino et al., 1990 Blumentals et al., 1990 Kegen et al., 1993 Laderman et al., 1993). 

For example, a ferredoxin hydrogenase (EC 1.12.7.2) has been isolated recently from the hyperthermophile Pyrococcus fUriosus [38]. The performance of this biocatalyst, which showed a remarkable stability under operative conditions, has been investigated for the NADPH regeneration in the reduction of prochiral ketones catalyzed by the thermophilic NADPH-dependent ADH from Thermoanaerohium sp. Total turnover numbers (TTNs mole product/mole consumed cofactor NADP" ") of 100 and 160 could be estimated in the reduction of acetophenone and (2S)-hydroxy-l-phenyl-propanone, respectively. As a side note, it should be mentioned that, although the activity of the P. furiosus hydrogenase increased exponentially with temperature up to its maximum above 80 °C, the reactions had to be performed at much lower temperature (40 °C) because of the thermal instability of NADPH. 

Mertens R, Greiner L, van den Ban ECD, Haaker H, Liese A. Practical applications of hydrogenase I from Pyrococcus furiosus for NADPH generation and regeneration. J Mol Catal B Enzym 2003 24-25 39-52. 

Pyrococcus endeavori (unpublished results ), hydrogenases from Methanococcus jannaschii and the extreme thermophile Methanococcus igneus, a-glucosidase from P. furiosus, glyceraldehyde-3-phosphate dehydrogenase from Thermotoga... 

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