RESUMEN
The structural gene encoding mature peptide of extracellular ? amylase was amplified from the genome DNA of hyperthermophilic archaeon Pyrococcus furiosus by PCR The recombinant plasmid pUC19 amy was constructed by inserting the amplified segment into vector pUC19 The recombinant vector pYX212 amy was constructed by ligate the heterogeneous fragment of pUC19 amy into the multiple cloning site of pYX212, an expression vector of yeast Saccharomyces cerevisiae W303 A1 were transformed with pYX212 amy by electroporation The transformant expressed the activity of the thermophilic ? amylase successfully The recombinant enzyme has the similar enzymatic properties as the extracellular ? amylase produced by Pyrococcus furiosus : it shows an enzymatic activity optimum at pH 5 0, and its optimal temperature for enzymatic activity is about 90℃, more than 50% of its initial enzymatic activity is still detectable after it was incubated at 121℃ for 30 minutes