Stability and sulfur-reduction activity in non-aqueous phase liquids of the hydrogenase from the hyperthermophilePyrococcus furiosus
| Autor: | Charlene A. Woodward, Eric N. Kaufman, Chulhwan Kim, Michael W. W. Adams |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Aqueous solution
Hydrogenase biology Chemistry Aqueous two-phase system Bioengineering biology.organism_classification Applied Microbiology and Biotechnology Medicinal chemistry Toluene Enzyme assay Hyperthermophile Enzyme catalysis chemistry.chemical_compound biology.protein Pyrococcus furiosus Organic chemistry Biotechnology |
| Zdroj: | Biotechnology and Bioengineering. 65:108-113 |
| ISSN: | 1097-0290 0006-3592 |
| Popis: | Hydrogenase from the hyperthermophilic archaeon, Pyrococcus furiosus, catalyzes the reversible activation of H(2) gas and the reduction of elemental sulfur (S degrees ) at 90 degrees C and above. The pure enzyme, modified with polyethylene glycol (PEG), was soluble (> 5 mg/mL) in toluene and benzene with t(1/2) values of more than 6 h at 25 degrees C. At 100 degrees C the PEG-modified enzyme was less stable in aqueous solution (t(1/2) approximately 10 min) than the native (unmodified) enzyme (t(1/2) approximately 1 h), but they exhibited comparable H(2) evolution, H(2) oxidation, and S degrees reduction activities at 80 degrees C. The H(2) evolution activity of the modified enzyme was twice that of the unmodified enzyme at 25 degrees C. The PEG-modified enzyme did not catalyze S degrees reduction (at 80 degrees C) in pure toluene unless H(2)O was added. The mechanism by which hydrogenase produces H(2)S appears to involve H(2)O as the proton source and H(2) as the electron source. The inability of the modified hydrogenase to catalyze S degrees reduction in a homogeneous non-aqueous phase complicates potential applications of this enzyme. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text