Expression and Characterization of a Thermostable α-Glucosidase from Hyperthermophile,Thermotoga maritima

Abstract:

A thermostable α-glucosidase gene aglA(TM1834) from a hyperthermophile bacterium,Thermotoga maritima,was expressed in Escherichia coli JM109 using the new heat-shock expression vector pHsh.The recombinant α-glucosidase aglA was purified by heat treatment,ion exchange chromatography,and hydrophobic chromatography,and had a molecular weight of 55 kDa as indicated by SDS-PAGE analysis.The optimum pH and temperature for this enzyme was pH 7.5 and 90 ℃,respectively.More than 50% was detected at pH values between 6.5 and 8.5 and temperatures between 65 ℃ and 100 ℃.The maximal aglA activity was observed in the presence of cofactor NAD+,Mn2+,and DTT.