Subsite Structure of Rhizopus Glucoamylase for the Hydrolytic Reaction of Isomaltooligosaccharides

概要

論文の詳細を見る
The subsite structure of Rhizopus glucoamylase was identified for the hydrolytic reaction of isomaltooligosaccharides at 25℃ and at pH 4. 5. The arrangement of the subsite affinities A_i's (i is the subsite number) was evaluated as follows : A_1= -6. 0, A_2=13. 8, A_3=4. 6, A_4=1.5, A_5=0.6, A_6= -0.5, and A_7 = 0.2 (in kJ mol^<-1> unit). The intrinsic rate constant for the hydrolytic reaction in the productive binding mode of substrates, k_<int>, was 10.2s^<-1>. Larger values of K_m for isomaltooligosaccharides compared with those for maltooligosaccharides were attributed to smaller values of A_1 and A_2 compared with those for maltooligosaccharides, and smaller values of k_0 were attributed to smaller values of A_1 and k_<int>. Steady-state inhibitory kinetic studies showed that both isomaltooligosaccharides and maltooligosaccharides bind to the same active site of the enzyme.
社団法人日本農芸化学会の論文
1994-10-23