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dc.contributor.authorPlant, Adrian R.
dc.contributor.authorClemens, Robyn M.
dc.contributor.authorDaniel, Roy M.
dc.contributor.authorMorgan, Hugh W.
dc.identifier.citationPlant, A.R., Clemens, R.M., Daniel, R.M. & Morgan, H.W. (1987). Purification and preliminary characterization of an extracellular pullulanase from Thermoanaerobium Tok6-B1. Applied Microbiology and Biotechnology, 26(5), 427-433.en_NZ
dc.description.abstractExtracellular pullulanase (pullulan 6-glucanohydrolase, EC was purified from cell free culture supernatants of Thermoanaerobium Tok6-B1 by ammonium sulphate precipitation, affinity precipitation, gel exclusion and ion exchange chromatography. A final purification factor of over 1600 was achieved. A molecular weight of 120 kD was determined by steric exclusion HPLC. Enzyme activity was specifically directed towards the 1–6 glucosidic linkages of pullulan resulting in 100% conversion to maltotriose and also possessed activity towards 1–4 linkages of starch, amylopectin and amylose producing maltooligosaccharides (DP2-DP4) as products. Maltotetraose was slowly hydrolysed to maltose. Values of K m (% w/v) were 7.3×10⁻³ for pullulan, 2.7×10⁻³ for amylopectin and 4.7×10⁻³ for Lintner's starch. Pullulanase activity was resistant to 6 M urea and was thermostable at temperatures up to 80°C (t 1/2 in the order of hours). Above 80°C thermal denaturation was significant (t 1/2=17 min at 85°C; 5 min at 90°C) but became less so in the presence of substrate (pullulan or starch). Thermostability was greatest at the pH activity optimum (pH 5.5) and was promoted by Ca²⁺ ions.en_NZ
dc.titlePurification and preliminary characterization of an extracellular pullulanase from Thermoanaerobium Tok6-B1en_NZ
dc.typeJournal Articleen_NZ

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