Purification and characterization of an extracellular amylase from a thermophilic streptomycete |
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Authors: | JD Goldberg C Edwards |
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Institution: | Department of Genetics and Microbiology, Life Sciences Building, The University, Liverpool L69 3BX, UK |
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Abstract: | G oldberg , J.D. & E dwards , C. 1990. Purification and characterization of an extracellular amylase from a thermophilic streptomycete. Journal of Applied Bacteriology 69 , 712–717. A single extracellular alpha-amylase (1,4-α-D-glucan glucanohydrolase, EC 3.2.1.1) from Streptomyces thermoviolaceus subsp. apingens was purified to homogeneity by a starch adsorption method. SDS-PAGE indicated that the enzyme had an apparent M, of 57 kDa and activity was optimal at a pH of 7–2 and a temperature of 55 C. It employed an endo-active mechanism to liberate predominantly maltose, as well as smaller amounts of higher oligosaccharides when incubated with starch. EDTA inhibited enzyme activity, suggesting an involvement of a divalent cation in activity. The enzyme was also stabilized by divalent cations when heated and the results suggested a major role for Ca2+ ions for both activity and thermostability. The alpha-amylase from S. thermoviolaceus displayed some similarities with commercially-used streptomycete alpha-amylases. |
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