title: Characterization of a Chitosanase from Jelly Fig (Ficus awkeotsang Makino) Latex and Its Application in the Production of Water-Soluble Low Molecular Weight Chitosans.
abstract: A chitosanase was purified from jelly fig latex by ammonium sulfate fractionation (50-80% saturation) and three successive column chromatography steps. The purified enzyme was almost homogeneous, as determined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and gel activity staining. The molecular mass of the enzyme was 20.5 kDa. The isoelectric point (pI) was <3.5, as estimated by isoelectric focusing electrophoresis on PhastGel IEF 3-9. Using chitosan as the substrate, the optimal pH for the enzyme reaction was 4.5; the kinetic parameters Km and Vmax were 0.089 mg mL-1 and 0.69 μmol min-1 mg-1, respectively. The enzyme showed activity toward chitosan polymers which exhibited various degrees of deacetylation (21-94%). The enzyme hydrolyzed 70-84% deacetylated chitosan polymers most effectively. Substrate specificity analysis indicated that the enzyme catalyzed the hydrolysis of chitin and chitosan polymers and their derivatives. The products of the hydrolysis of chitosan polymer derivatives, ethylene glycol (EG) chitosan, carboxymethyl (CM) chitosan and aminoethyl (AE) chitosan, were low molecular weight chitosans (LMWCs); these products were referred to as EG-LMWC, CM-LMWC and AE-LMWC, respectively. The average molecular weights of EG-LMWC, CM-LMWC and AE-LMWC were 11.2, 11.2 and 8.89 kDa, respectively. All of the LMWC products exhibited free radical scavenging activities toward ABTS•+, superoxide and peroxyl radicals.
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, Republic of China (Taiwan).
authors.forename: Chen-Tien
authors.initials: CT
authors.lastname: Chang
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, Republic of China (Taiwan).
authors.forename: Yen-Lu
authors.initials: YL
authors.lastname: Lin
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, Republic of China (Taiwan).
authors.forename: Shu-Wei
authors.initials: SW
authors.lastname: Lu
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, Republic of China (Taiwan).
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Huang
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, Republic of China (Taiwan).
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, Republic of China (Taiwan).
authors.forename: Yun-Chin
authors.initials: YC
authors.lastname: Chung
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D052160:Benzothiazoles / Q000037:antagonists & inhibitors; D002686:Chitin / Q000737:chemistry; D048271:Chitosan / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D030681:Ficus / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007526:Isoelectric Point; D007700:Kinetics; D007840:Latex / Q000737:chemistry*; D008970:Molecular Weight; D010545:Peroxides / Q000037:antagonists & inhibitors; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D012995:Solubility; D013379:Substrate Specificity; D013451:Sulfonic Acids / Q000037:antagonists & inhibitors; D013481:Superoxides / Q000037:antagonists & inhibitors; D014867:Water
chemical_list: D052160:Benzothiazoles; D016166:Free Radical Scavengers; D007840:Latex; D010545:Peroxides; D010940:Plant Proteins; D013451:Sulfonic Acids; C514968:carboxymethyl-chitosan; C118638:glycol-chitosan; D014867:Water; D013481:Superoxides; D002686:Chitin; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C049375:perhydroxyl radical; D048271:Chitosan; D006026:Glycoside Hydrolases; C019868:chitosanase; D000645:Ammonium Sulfate