Biomaterial Database

Immobilization of acid phosphatase on uncalcined and calcined Mg/Al-CO(3) layered double hydroxides. 2010

Jun Zhu, and Qiaoyun Huang, and Massimo Pigna, and Antonio Violante

Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.

Acid phosphatase was immobilized on layered double hydroxides of uncalcined- and calcined-Mg/Al-CO(3) (Unc-LDH-CO(3), C-LDH-CO(3)) by the means of direct adsorption. Optimal pH and temperature for the activity of free and immobilized enzyme were exhibited at pH 5.5 and 37 degrees C. The Michaelis constant (K(m)) for free enzyme was 1.09 mmol mL(-1) while that for immobilized enzyme on Unc-LDH-CO(3) and C-LDH-CO(3) was increased to 1.22 and 1.19 mmol mL(-1), respectively, indicating the decreased affinity of substrate for immobilized enzymes. The residual activity of immobilized enzyme on Unc-LDH-CO(3) and C-LDH-CO(3) at optimal pH and temperature was 80% and 88%, respectively, suggesting that only little activity was lost during immobilization. The deactivation energy (E(d)) for free and immobilized enzyme on Unc-LDH-CO(3) and C-LDH-CO(3) was 65.44, 35.24 and 40.66 kJ mol(-1), respectively, indicating the improving of thermal stability of acid phosphatase after the immobilization on LDH-CO(3) especially the uncalcined form. Both chemical assays and isothermal titration calorimetry (ITC) observations implied that hydrolytic stability of acid phosphatase was promoted significantly after the immobilization on LDH-CO(3) especially the calcined form. Reusability investigation showed that more than 60% of the initial activity was remained after six reuses of immobilized enzyme on Unc-LDH-CO(3) and C-LDH-CO(3). A half-life (t(1/2)) of 10 days was calculated for free enzyme, 55 and 79 days for the immobilized enzyme on Unc-LDH-CO(3) and C-LDH-CO(3) when stored at 4 degrees C. Therefore, immobilization of acid phosphatase on Unc-LDH-CO(3) and C-LDH-CO(3) by direct adsorption is an effective means and would have promising potential for the practical application in agricultural production and environmental remediation.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008855	Microscopy, Electron, Scanning	Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.	Scanning Electron Microscopy,Electron Scanning Microscopy,Electron Microscopies, Scanning,Electron Microscopy, Scanning,Electron Scanning Microscopies,Microscopies, Electron Scanning,Microscopies, Scanning Electron,Microscopy, Electron Scanning,Microscopy, Scanning Electron,Scanning Electron Microscopies,Scanning Microscopies, Electron,Scanning Microscopy, Electron
D011198	Solanum tuberosum	A plant species of the genus SOLANUM, family SOLANACEAE. The starchy roots are used as food. SOLANINE is found in green parts.	Potatoes,Potato,Solanum tuberosums,tuberosum, Solanum,tuberosums, Solanum
D002151	Calorimetry	The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D004800	Enzymes, Immobilized	Enzymes which are immobilized on or in a variety of water-soluble or water-insoluble matrices with little or no loss of their catalytic activity. Since they can be reused continuously, immobilized enzymes have found wide application in the industrial, medical and research fields.	Immobilized Enzymes,Enzyme, Immobilized,Immobilized Enzyme
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D006878	Hydroxides	Inorganic compounds that contain the OH- group.
D000135	Acid Phosphatase	An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.2.	Acid beta-Glycerophosphatase,Acid beta Glycerophosphatase