α-Amylase activity from the halophilic archaeon Haloferax mediterranei
- 24 April 2003
- journal article
- Published by Springer Nature in Extremophiles
- Vol. 7 (4) , 299-306
- https://doi.org/10.1007/s00792-003-0327-6
Abstract
The halophilic archaeon Haloferax mediterranei is able to grow in a minimal medium containing ammonium acetate as a carbon and nitrogen source. When this medium is enriched with starch, α-amylase activity is excreted to the medium in low concentration. Here we report methods to concentrate and purify the enzyme. The relative molecular mass of the enzyme, determined by gel filtration, is 50±4 kDa, and on SDS-PAGE analysis a single band appeared at 58 kDa. These results indicated that the halophilic α-amylase is a monomeric enzyme. The enzyme showed a salt requirement for both stability and activity, being stable from 2 to 4 M NaCl, with maximal activity at 3 M NaCl. The enzyme displayed maximal activity at pHs from 7 to 8, and its optimal temperature was in a range from 50 °C to 60 °C. The results also implicated several prototropic groups in the catalytic reaction.Keywords
This publication has 43 references indexed in Scilit:
- Extreme halophilic enzymes in organic solventsCurrent Opinion in Biotechnology, 2002
- Protein engineering of bacterial α-amylasesBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 2000
- Crystal structure of yellow meal worm α-amylase at 1.64 Å resolutionJournal of Molecular Biology, 1998
- Molecular structure of a barley α-amylase-inhibitor complex: implications for starch binding and catalysisJournal of Molecular Biology, 1998
- Extracellular α-amylase from Thermus filiformis Ork A2: purification and biochemical characterizationExtremophiles, 1998
- Glycosyl hydrolases from hyperthermophilesExtremophiles, 1997
- Glucose dehydrogenase from the halophilic Archaeon Haloferax mediterranei: Enzyme purification, characterisation and N‐terminal sequenceFEBS Letters, 1996
- Isocitrate dehydrogenases from Haloferax volcanii and Sulfolobus solfataricus: enzyme purification, characterisation and N-terminal sequenceFEMS Microbiology Letters, 1995
- Crystal Structure of Calcium-depletedBacillus licheniformisα-amylase at 2.2 Å ResolutionJournal of Molecular Biology, 1995
- Chemical and kinetic mechanisms of aspartate-β-semialdehyde dehydrogenase from Escherichia coliBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1991