title: Autocatalytic reaction in hydrolysis of difructose anhydride III.
abstract: Hydrolysis of several polysaccharides in neutral and weak acid environment has been shown to exhibit autocatalytic behavior. Because the pH value of the solution decreases during hydrolysis, it has been proposed that proton is the catalyst of the autocatalytic reaction. We monitored the hydrolysis of difructose anhydride III (DFA III) in both strong and weak acid environment using Raman spectroscopy and found that it is also an autocatalytic reaction. Its Raman signatures were analyzed with ab initio method. When the reaction product, fructose, is added in the beginning of the reaction, the speed of hydrolysis increases to a magnitude that cannot be explained by the rate enhancement due to a decrease in the pH value, indicating that proton alone is not an effective catalyst for the reaction. It is the combination of proton and a certain form of reaction product such as monosaccharide or its derivatives that catalyzes the hydrolysis of difructose anhydride III. Similar results are observed in the hydrolysis of cellobiose, suggesting the universality of this autocatalytic reaction. Our findings provide the first clue to a new autocatalytic pathway in the hydrolysis of polysaccharides.
authors.affiliation: Institute of Atomic and Molecular Sciences, Taiwan International Graduate Program, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.
authors.forename: Tzu-Hsin
authors.initials: TH
authors.lastname: Chan
authors.forename: Po-Tuan
authors.initials: PT
authors.lastname: Chen
authors.forename: Hsuan-Hau
authors.initials: HH
authors.lastname: Chang
authors.forename: Ming-Yu
authors.initials: MY
authors.lastname: Lai
authors.forename: Michitoshi
authors.initials: M
authors.lastname: Hayashi
authors.forename: Juen-Kai
authors.initials: JK
authors.lastname: Wang
authors.forename: Yuh-Lin
authors.initials: YL
authors.lastname: Wang
mesh_terms: D002384:Catalysis; D004187:Disaccharides / Q000737:chemistry* / Q000378:metabolism; D005632:Fructose / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008968:Molecular Conformation; D011789:Quantum Theory; D012996:Solutions; D013059:Spectrum Analysis, Raman
chemical_list: D004187:Disaccharides; D012996:Solutions; D005632:Fructose; C087758:difructose anhydride III