Enzymatic degradation of cyclic 2,3-diphosphoglycerate to 2,3-diphosphoglycerate in Methanobacterium thermoautotrophicum
| Autor: | Musti V. Krishna Sastry, Mary F. Roberts, James A. Moynihan, Diane E. Robertson |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Lysis
Magnetic Resonance Spectroscopy Stereochemistry Hydrolases Methanobacteriaceae Kinetics Biochemistry Dithiothreitol Chromatography Affinity Potassium Chloride Chemical kinetics Hydrolysis chemistry.chemical_compound Affinity chromatography Enzymatic hydrolysis Organic chemistry 2 3-Diphosphoglycerate biology Methanobacterium Temperature biology.organism_classification Diphosphoglyceric Acids Oxygen chemistry Spectrophotometry |
| Zdroj: | Biochemistry. 31(11) |
| ISSN: | 0006-2960 |
| Popis: | 2,3-Diphosphoglycerate (2,3-DPG) has been found to be the product of the enzymatic degradation of cyclic 2,3-diphosphoglycerate (cDPG) in the archaebacterium Methanobacterium thermoautotrophicum delta H. Although 2,3-DPG has not previously been detected as a major soluble component of M. thermoautotrophicum, large pools accumulated at an incubation temperature of 50 degrees C (below the optimum growth temperature of 62 degrees C). Under these conditions, cellular activity was significantly decreased; a return of the culture to the optimum growth temperature restored the 2,3-DPG pool back to original low levels and caused steady-state cDPG levels to increase again. While 13CO2-pulse/12CO2-chase experiments at 50 degrees C showed that the cDPG turned over, the appearance of 2,3-DPG at NMR-visible concentrations required at least 10 h. Production of 2,3-DPG in vivo was prevented by exposure of the cells to O2. The enzyme responsible for this hydrolysis of cDPG was purified by affinity chromatography and appears to be a 33-kDa protein. Activity was detected in the presence of oxygen and was enhanced by a solution of 1 M KCl, 25 mM MgCl2, and dithiothreitol. Both Km and Vmax have been determined at 37 degrees C; kinetics also indicate that in vitro the product, 2,3-DPG, is an inhibitor of cDPG hydrolysis. These findings are discussed in view of a proposed role for cDPG in methanogens. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|