Regulation of Escherichia coli formate hydrogenlyase activity by formate at alkaline pH
| Autor: | Liparit Navasardyan, Anait Vassilian, Karine Bagramyan, Nelli Mnatsakanyan, Armen Trchounian |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Hydrogenase
Formates Intracellular pH Alkalies medicine.disease_cause Applied Microbiology and Biotechnology Microbiology chemistry.chemical_compound Adenosine Triphosphate Multienzyme Complexes medicine Escherichia coli Formate Chemistry Escherichia coli Proteins General Medicine Hydrogen-Ion Concentration Decomposition Formate Dehydrogenases Membrane Biochemistry Gene Expression Regulation Potassium Formate hydrogenlyase Fermentation Hydrogen |
| Zdroj: | Current microbiology. 45(4) |
| ISSN: | 0343-8651 |
| Popis: | Escherichia coli possesses two hydrogenases, Hyd-3 and Hyd-4. These, in conjunction with formate dehydrogenase H (Fdh-H), constitute distinct membrane-associated formate hydrogenlyases, FHL-1 and FHL-2, both catalyzing the decomposition of formate to H2 and CO2 during fermentative growth. FHL-1 is the major pathway at acidic pH whereas FHL-2 is proposed for slightly alkaline pH. In this study, regulation of activity of these pathways by formate has been investigated. In cells grown under fermentative conditions on glucose in the presence of 30 mM formate at pH 7.5, intracellular pH was decreased to 7.1, the activity of Fdh-H raised 3.5-fold, and the production of H 2 became mostly Hyd-3 dependent. These results suggest that at alkaline pH formate increases an activity of Fdh-H and of Hyd-3 both but not of Hyd-4. Escherichia coli carrying out a mixed-acid fermentation of glucose produces formate among the other products that can be excreted via the formate channel, or can be further metabolized to H2 and CO2 by the membrane- associated formate hydrogenlyase (FHL). Two FHL pathways, FHL-1 and FHL-2, are proposed. |
| Databáze: | OpenAIRE |
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