Purification and properties of a new exo-(1.3)- -D-glucanase from Bacillus circulans YK9 capable of hydrolysing resistant curdlan with formation of only laminari-biose
| Autor: | Takashi Kurasawa, Yukihiro Kanegae, Tokuya Harada, Akira Harada, Yoshimi Kanzawa |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
chemistry.chemical_classification
beta-Glucans Chromatography Molecular mass Hydrolysis beta-Glucosidase Bacillus Glucan 1 3-beta-Glucosidase Curdlan Hydrogen-Ion Concentration Glucanase Disaccharides Polysaccharide Microbiology Schizophyllan Substrate Specificity Molecular Weight chemistry.chemical_compound Enzyme chemistry Bacillus circulans Glucans |
| Zdroj: | Microbiology. 140:637-642 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/00221287-140-3-637 |
| Popis: | A (1--3)-beta-D-glucan glucanohydrolase (EC 3.2.1.6), capable of hydrolysing resistant curdlan, was purified chromatographically from the culture supernatant of Bacillus circulans complex YK9 on Toyopearl HW-55F and butyl-Toyopearl 650M columns. The purified enzyme had a specific activity of 190 units mg-1 on regenerated curdlan. The molecular mass was estimated to be about 70 kDa as judged by SDS-PAGE. The enzyme had a pH optimum of approximately pH 6.0. It hydrolysed regenerated and resistant curdlans yielding predominantly laminari-biose, although the rate of hydrolysis of the former was much higher than the latter. This enzyme rapidly hydrolysed laminaran, curdlan and carboxymethyl-curdlan, but did not cleave schizophyllan and screloglucan, which have glucosyl side chains. The enzyme hydrolysed low molecular mass (1--3)-beta-D-glucans-(mean degree of polymerization, DPn = 131, 49 and 14) and laminari-heptaose more efficiently than curdlan. It also hydrolysed laminari-hexaose and -pentaose effectively, but laminari-tetraose only slightly and it did not hydrolyse laminari-triose or -biose. The enzyme is an exo-hydrolase of curdlan and various oligomers composed of (1--3)-beta-D-glucosidic linkages, liberating laminari-biose from their non-reducing terminals. The laminari-biose generated was in the alpha-form. |
| Databáze: | OpenAIRE |
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