Purification and characterization of a thermostable alpha-amylase from Bacillus licheniformis
| Autor: | E. Emanuilova, E. Dobreva, Viara Ivanova |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
chemistry.chemical_classification
Chromatography Molecular mass biology Size-exclusion chromatography Ion chromatography Bioengineering General Medicine biology.organism_classification Applied Microbiology and Biotechnology Michaelis–Menten kinetics Enzyme chemistry biology.protein Bacillus licheniformis Alpha-amylase Biotechnology Thermostability |
| Zdroj: | Journal of Biotechnology. 28:277-289 |
| ISSN: | 0168-1656 |
| DOI: | 10.1016/0168-1656(93)90176-n |
| Popis: | The extracellular alpha-amylase produced by the Bacillus licheniformis 44MB82-A strain was isolated. The enzyme was purified by two-phase separation in a PEG-Dextran system, followed by gel-filtration and ion exchange chromatography. Its molecular mass was determined as 58000 by SDS-PAGE and gel filtration. The enzyme was stable at pH values from 6.5 to 8.0 and its pH optimum was pH 6.0–6.5. The temperature optimum was determined as 90°C. The Michaelis constant for soluble starch was measured as 0.90 g l −1 . Thermostability was Ca 2+ -dependent. The half-life of the purified enzyme was 10 min at 85°C in buffer without Ca 2+ . The half-life at pH 6.5 with 1.0 mM CaCl 2 added was 30 min, and over 120 min with 5.0 mM CaCl 2 . The purified enzyme was strongly inhibited by N -bromosuccinimide (NBS) and by EDTA. Dithiothreitol and iodacetamide had no inhibitory effect on the purified enzyme. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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