The gene encoding a family-57-like α-amylase in the hyperthermophilic archaeon Methanococcus jannaschii, has been cloned into Escherichia coli. Extremely thermoactive α-amylase was confirmed in partially purified enzyme solution of the recombinant culture. This enzyme activity had a temperature optimum of 120°C and a pH optimum 5.0-8.0. The amylase activity is extremely stable against denaturants. Hydrolysis of large sugar polymers with α-1-6 and α-1-4 linkages yields products including glucose polymers of 1-7 units. Highest activity is exhibited on amylose. The catalyst exhibited a half-life of 50 h at 100°C, among the highest reported thermostabilities of natural amylases.
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