Thermostable inulin fructotransferase(DFA Ill-producing)from Arthrobacter sp.L68-1

摘要

An inulin fructotransferase(DFA III-producing)[EC 2.4.1.93]from Arthrobacter sp.L68-1 was purified and characterised.The enzyme was purified from culture supernatant of the microorganism 54.2-fold with a yield of 16.0% using DEAE-Toyopearl chromatography(repeated twice)and Super Q-Toyopearl chromatography.The enzyme showed maximum activity at pH 5.5-6.0 and 55 deg C.The enzyme activity was stable up to 80 deg C after 1 h heat treatment.This heat stability was the highest of the inulin fructotransferases(DFA Ill-producing)reported to date.The molecular mass of the enzyme was estimated to be 43 kDa by SDS-PAGE and 73 kDa by gel filtration,and was considered to be a dimer.The N-terminal amino acid sequence(18 amino acid residues)was determined as AEETKGGPFNSPNAYDVT.