SCHURIG, H and RUTKAT, K and RACHEL, R and JAENICKE, R (1995) OCTAMERIC ENOLASE FROM THE HYPERTHERMOPHILIC BACTERIUM THERMOTOGA-MARITIMA - PURIFICATION, CHARACTERIZATION, AND IMAGE-PROCESSING. PROTEIN SCIENCE, 4 (2). pp. 228-236. ISSN 0961-8368,
Full text not available from this repository.Abstract
Enolase (2-phospho-D-glycerate hydrolase; EC 4.2.1.11) from the hyperthermophilic bacterium Thermotoga maritima was purified to homogeneity. The N-terminal 25 amino acids of the enzyme reveal a high degree of similarity to enolases from other sources. As shown by sedimentation analysis and gel-permeation chromatography, the enzyme is a 345-kDa homooctamer with a subunit molecular mass of 48 +/- 5 kDa. Electron microscopy and image processing yield ring-shaped particles with a diameter of 17 nm and fourfold symmetry. Averaging of the aligned particles proves the enzyme to be a tetramer of dimers. The enzyme requires divalent cations in the activity assay, Mg2+ being most effective. The optimum temperature for catalysis is 90 degrees C, the temperature dependence yields a nonlinear Arrhenius profile with limiting activation energies of 75 kJ mol(-1) and 43 kJ mol(-1) at temperatures below and above 45 degrees C. The pH optimum of the enzyme lies between 7 and 8. The apparent K-m values for 2-phospho-D-glycerate and Mg2+ at 75 degrees C are 0.07 mM and 0.03 mM; with increasing temperature, they are decreased by factors 2 and 30, respectively. Fluoride and phosphate cause competitive inhibition with a K-i of 0.14 mM. The enzyme shows high intrinsic thermal stability, with a thermal transition at 90 and 94 degrees C in the absence and in the presence of Mg2+.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | D-GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE; YEAST ENOLASE; LACTATE-DEHYDROGENASE; ESCHERICHIA-COLI; RECONSTITUTION; TEMPERATURE; ENZYMES; INHIBITION; RESOLUTION; FLUORIDE; ENOLASE; GLYCOLYSIS; THERMOSTABILITY; THERMOTOGA MARITIMA |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:38 |
| URI: | https://pred.uni-regensburg.de/id/eprint/52781 |
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