Effects Of Several Low-Molecular-Weight Organic Acids And Phosphate On The Adsorption And Activity Of BSA And Acid Phosphatase On Soil Colloids And Minerals

The effect of the concentration, pH of several ligands such as acetate, oxalate, tartrate and phosphate solution and their orders added on the adsorption and activity of BSA and acid phosphatase on yellow brown soil, latosol, kaolinite, goethite and -MnO2 was first systematically studied by using batch and FTIR methods after analyzed and studied the relative literature that reported in the world. The impact of these ligands on the adsorption mechanism and secondary structure of protein was simultaneously engaged. These studies have important significances in scientific field and practice for probe into interaction mechanism of the relate compositions in the adsorption of BSA and enzyme and for clarification the factors affecting soil enzyme activity, as well as for improving soil fertility and environmental quality. Some main results and progressions are illustrated as follows:1. The results of FTIR in vacuum for the first time indicated that: Both oxalate and goethite surface can make the -sheet of BSA decrease, and make that of random bent increase of BSA. The effect action of oxalate and goethite surface on the content of abnormity -sheet, -helix and -turn structure in BSA was contrary, whereas the goethite surface can make the ordered structure increase of BSA, and it related nearly to the concentration of BSA added into the system. Oxalate can make the increase of C=O in hydrophobic situation of BSA, and make the decrease of C=O in polar situation of BSA. However, the action of goethite surface in this aspect was contrary.2. The quick-speed and accurate method provided by author such as 1). Suspension prepared by adding deionized water into soil colloids and minerals tested to be dispersed by ultrasonic and magnetic force stirrer, sucked with finnpipette to get quantitative soil colloids and minerals was validity; 2). The method by adjusting the pH of each sample solution before mixing them can control the pH of reaction system in the true sense.3. In the research of effects of ligands on adsorption and activity of protein and enzyme on soil colloids and minerals studied, we elucidated for the first time that: The influencing degree of ligands on adsorption and activity of protein and enzyme were depended on surface type of colloids, the kind of protein and enzyme, the magnitude ligand, the content of function group, the concentration and pH of lignad solution, and the addition order of ligands and enzyme and so on.1) First revealed that: (1) there were stimulative action of acetate in low concentration(<10mmol/L) for proteins adsorption on the surface of soil colloids and minerals studied whereas the weak restraint action would be happened when acetate concentration was over 10 mmol/L; (2) For oxalate system, the adsorption amount of protein firstly decreased (0-5mmol/L), followed with an increment (>5mmol/L); (3) For the tartrate and phosphate system, with the concentration of them increasing, the amount of protein adsorbed by colloids tested would be depressed considerably and progressively. (4) Phosphate shows the greatest impact for the adsorption of protein on Fe oxide surface whereas the tartrate may pose a greater effect on the protein adsorption for other sorts of surfaces, such as layer aluminum silicate minerals. One found that the selectivity of soil colloids and minerals for the protein adsorption would be caused by the presence of different anion ligands in system. This proved that the protein adsorption on the surface of soil colloids and minerals at a certain degree depend upon the surface type of colloids, the molecular magnitude and function group of ligands.2). Elucidated that: (1) The type of adsorption isotherm related nearly to the kind and concentration of ligands. (2) In acetate, oxalate and low concentrations of tartrate and phosphate solution, the adsorption isotherms for the proteins on soil colloids and minerals tested conformed to the Langmuir model (L or H type) whereas a linear (C type) adsorption isotherm was obtained at higher concentrations of ta...