Qualitative enzymatic detection of organophosphate and carbamate insecticides.

In this study, new polymers containing amides (TrisPS-Ntaa, and TrisPS-Ntaa-Fc) were synthesized by condensation reaction for qualitative identification of insecticides. The synthesized polymers, including amides were investigated by infrared spectroscopy (IR), scanning electron microscopy-energy dispersion X- ray spectrometry (SEM-EDX), and gel permeation chromatography (GPC). Then, acetylcholinesterase enzyme (AChE) was covalently immobilized on these polymers to improve properties (including activity, reusability, and storage stability). Accordingly, organophosphate (malathion, acephate, chlorpyrifos methyl) and carbamate (carbofuran, methiocarb, methomyl), which are used to prevent harmful organisms in some agricultural products were enzymatically determined based on their inhibitory activity on AChE.

Novel polymeric microspheres: Synthesis, enzyme immobilization, antimutagenic activity, and antimicrobial evaluation against pathogenic microorganisms.

New polymeric microspheres containing azomethine (1a-1c and 2a-2c) were synthesized by condensation to compare the enzymatic properties of the enzyme glucose oxidase (GOx) and to investigate antimutagenic and antimicrobial activities. The polymeric microspheres were characterized by elemental analysis, infrared spectra (FT-IR), proton nuclear magnetic resonance spectra, thermal gravimetric analysis, and scanning electron microscopy analysis. The catalytic activity of the glucose oxidase enzyme follows Michaelis-Menten kinetics. Influence of temperature, reusability, and storage capacity of the free and immobilized glucose oxidase enzyme were investigated. It is determined that immobilized enzymes exhibit good storage stability and reusability. After immobilization of GOx in polymeric supports, the thermal stability of the enzyme increased and the maximum reaction rate (Vmax ) decreased. The activity of the immobilized enzymes was preserved even after 5 months. The antibacterial and antifungal activity of the polymeric microspheres were evaluated by well-diffusion method against some selected pathogenic microorganisms. The antimutagenic properties of all compounds were also examined against sodium azide in human lymphocyte cells by micronuclei and sister chromatid exchange tests.

Nanoplatforms attached Schiff bases by condensation method; Investigation of glucose oxidase enzyme as biocatalysts.

We report a easy approach for the immobilization of glucose oxidase enzyme (GOx) on nanoparticles. Nanoparticles-modified polystyrene-ANH2 (PSA) with some salicylaldehyde derivatives were synthesized by means of condensation and investigated the enzymatic properties of GOx immobilized on there. Modified polystyrenes were characterized using IR spectra, gel permeation chromatography, and scanning electron microscopy. All the characteristics of the immobilized glucose oxidase (PSA-SalH)-GOx, (PSA-SalCH3)-GOx, and (PSA)-GOx enzyme showed except one of them. Immobilized GOx on to (PSA) showed two optimum pH, other immobilized polymers were one optimum.

Binding multidentate ligands to Ni2+: kinetic identification of preferential binding sites.

The kinetics of the reactions between [Ni(MeOH)6](2+) (hereafter Ni(2+)) and a variety of neutral Schiff base multidentate ligands have been measured in methanol at 25.0 °C using stopped-flow spectrophotometry. The ligands contain a variety of different potential donor sites (phenolic OH, imine N, pyridyl N and NH groups), different structural components and substituents. The kinetic studies explore how systematic changes to the composition of the ligands affect the rates of binding. The results are consistent with the Eigen-Wilkins mechanism in which the ligand initially forms an outer-sphere association with Ni(2+) prior to dissociation of a coordinated solvent molecule and binding to the metal ion. The general features that emerge from these studies are as follows. (i) For ligands with the same donor set, the rates of binding are all similar irrespective of changes to the ligand framework (bridge and substituents). (ii) Comparison of structurally analogous ligands shows that the presence of pyridyl or NH groups in the multidentate results in significantly faster reactions. (iii) With ligands containing multiple NH groups, the rate of ligand binding increases as the number of NH groups increases. The extent to which these kinetic features can be attributed to preferential binding of particular donor groups is discussed.

Polystyrene attached Pt(IV)-azomethine, synthesis and immmobilization of glucose oxidase enzyme.

Modified polystyrene with Pt(IV)-azomethine (APS-Sch-Pt) was synthesized by means of condensation and demonstrated to be a promising enzyme support by studying the enzymatic properties of glucose oxidase enzyme (GOx) immobilized on it. The characteristics of the immobilized glucose oxidase (APS-Sch-Pt-GOx) enzyme showed two optimum pH values that were pH = 4.0 and pH = 7. The insertion of stable Pt(IV)-azomethine spacers between the polystyrene backbone and the immobilized GOx, (APS-Sch-Pt-GOx), increases the enzymes' activity and improves their affinity towards the substrate even at pH = 4. The influence of temperature, reusability and storage capacity on the free and immobilized glucose oxidase enzyme was investigated. The storage stability of the immobilized glucose oxidase was shown to be eleven months in dry conditions at +4 °C.

Novel polymer anchored Cr(III) Schiff base complexes: synthesis, characterization and antimicrobial properties.

New polymer-bound Schiff bases and Cr(III) complexes have been synthesized by the reaction of 4-benzyloxybenzaldehyde, polymer-bound with 2-aminophenol, 2-amino-4-chlorophenol and 2-amino-4-methylphenol. The structure of polymeric-Schiff bases and their Cr(III) complexes have been characterized by elemental analyses, magnetic measurements, IR, UV-Vis, TG-DTA and (1)H-NMR. All these compounds have also been investigated for antibacterial activity by the well-diffusion method against Staphylococcus aureus (RSKK-07035), Shigella dysenteria type 10 (RSKK 1036), Listeria monocytogenes 4b(ATCC 19115, Escherichia coli (ATCC 1230), Salmonella typhi H (NCTC 901.8394), Staphylococcus epidermis (ATCC 12228), Brucella abortus (RSKK-03026), Micrococcs luteus (ATCC 93419, Bacillus cereus sp., Pseudomonas putida sp. and for antifungal activity against Candida albicans (Y-1200-NIH).