Inulin fructotransferase (DFA III-producing) from Leifsonia sp. T88-4

An inulin fructotransferase (DFA III-producing) [EC 2.4.1.93] from Leifsonia sp. T88-4 was purified and characterized, for the first time. The enzyme was purified from culture supernatant of the microorganism 32.4-fold with a yield of 11.3% using a DEAE–Toyopearl chromatography and two times of Super Q-Toyopearl chromatography. The enzyme showed maximum activity at pH 5.0 and 65 °C. This maximum temperature was highest in the inulin fructotransferase (DFA III-producing) reported to date. The enzyme activity was stable up to 60 °C after 30 min heat treatment. The molecular mass of the enzyme was estimated to be 44 kDa by SDS–PAGE and 74 kDa by gel filtration, and was considered to be a dimer. The N-terminal amino acid sequence (16 amino acid residues) was determined as METNVYDVTDVGVPGR. The Km value of the reaction at pH 5.0 and 60 °C was estimated to be 1.0 mM.