Purification and Subsite Affinities of exo-Inulinase from Penicillium trzebinskii

概要

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An exo-inulinase was highly purified from the culture broth of Penicillium trzebinskii by anion exchange, hydrophobic, and gel filtration chromatographies. The enzyme was homogeneous by disc electrophoresis. The molecular weight was 8.7×10^4,and the isoelectric point was pH 4.3. The enzyme hydrolyzed not only inulin and sucrose but also inulooligosaccharides [1^F(1-β-D-fructofuranosyl)_<n-1>fructose, F_n(n=2-5)] and fructooligosaccharides [1^F(1-β-D-fructofuranosyl)_<n-1> sucrose, GF_n, (n=2-8)] liberating the nonreducing terminal fructose of the substrates. The substrate specificity was investigated. The K_m (mM) and κ_0 (sec^<-1>) were : inulin, 0.042 and 159 ; sucrose, 6.5 and 169 ; F_2,2.1 and 62.8 ; F_3,0.40 and 126 ; F_4,0.47 and 171 ; and F_5,0.47 and 131,respectively. Dependence of K_m and κ_0 values on the degree of polymerization of substrates was observed. The subsite affinities in the active site were 1.05,4.57,1.45,0.09,and -0.16 kcal/mol for subsite 1,2,3,4,and 5,respectively.
社団法人日本農芸化学会の論文
1992-09-23