pectins and metaperiodate

Pectin was modified by oxidation with sodium periodate at molar ratios of 2.5, 5, 10, 15 and 20 mol% and reductive amination with tyramine and sodium cyanoborohydride afterwards. Concentration of tyramine groups within modified pectin ranged from 54.5 to 538 μmol/g of dry pectin while concentration of ionizable groups ranged from 3.0 to 4.0 mmol/g of dry polymer compared to 1.5 mmol/g before modification due to the introduction of amino group. All tyramine-pectins showed exceptional gelling properties and could form hydrogel both by cross-linking of carboxyl groups with calcium or by cross-linking phenol groups with peroxidase in the presence of hydrogen peroxide. These hydrogels were tested as carriers for soybean hull peroxidase (SHP) immobilization within microbeads formed in an emulsion based enzymatic polymerization reaction. SHP immobilized within tyramine-pectin microbeads had an increased thermal and organic solvent stability compared to the soluble enzyme. Immobilized SHP was more active in acidic pH region and had slightly decreased K

Topics: Borohydrides; Enzymes, Immobilized; Equipment Reuse; Glycine max; Hydrogels; Hydrogen Peroxide; Hydrogen-Ion Concentration; Kinetics; Oxidation-Reduction; Pectins; Periodic Acid; Peroxidase; Plant Proteins; Tyramine; Waste Products

A water-soluble polysaccharide (RP-1) was obtained from distilled rose petals of Rosa damascena Mill. as an attempt for valorization of the waste. RP-1 showed in vitro intestinal immune system modulating activity through Peyer's patch cells and IL-6 producing activity from macrophages. RP-1 lost most of its immunomodulating activity by degradation of the carbohydrate moiety with periodate. RP-1 was fractionated by anion-exchange and gel filtration chromatography and some of the fractions showed significant intestinal immune system modulating activity. The active fractions were suggested to be pectic polysaccharides and type II arabino-3,6-galactan from the component sugar analyses and the reactivity with Yariv antigen. When some active fractions were digested with endo α-d-(1→4)-polygalacturonase, highest molecular weight fragments which were considered as rhamnogalacturonan I, showed potent immunomodulating activities. To our knowledge, this is a first report which explores the possibility for utilization of waste rose petals as a source of immunomodulating pectic polysaccharides.

Topics: Animals; Cells, Cultured; Chromatography, Ion Exchange; Female; Galactans; Immunomodulation; Industrial Waste; Interleukin-6; Macrophages; Mice; Pectins; Periodic Acid; Peyer's Patches; Polygalacturonase; Rosa

High methoxy citrus pectin was oxidized by periodic acid to prepare a dialdehyde functionalized material. The effect of various reaction conditions, viz., reaction time, reaction temperature, pH of the medium, periodic acid concentration and solvent composition on the oxidation process was investigated. With an increase in the reaction time, the aldehyde content increased. However, the intrinsic viscosity of the system decreased indicating that degradation takes place simultaneously with oxidation. The amount of aldehyde generated also increased with an increase in reaction temperature and the concentration of periodic acid. Due to the polyanionic behaviour of pectin, greater aldehyde contents were obtained at lower pH. Keeping all other reaction conditions constant, greater aldehyde contents were obtained in water-ethanol system than in pure aqueous medium. Increase in the ethanol content increased the amount of aldehyde generated. FTIR spectra of oxidized pectin systems show a carbonyl peak at 1734 cm(-1). They further reveal that partial ionisation of-COOH groups takes place leading to a peak at 1614 cm(-1).

Topics: Aldehydes; Hydrogen-Ion Concentration; Kinetics; Oxidation-Reduction; Pectins; Periodic Acid; Solvents; Temperature

In this paper, we further analysed the structure of a type I rhamnogalacturonan (RG-I) pectin (WGPA-2-RG) fractionated from ginseng polysaccharides. Methylation and periodate oxidation analyses showed that WGPA-2-RG has a backbone consisting of alternating rhamnose (Rha) and galacturonic acid (GalA) residues and side chains consisting of type II arabinogalactan (AG-II). Partial acidic hydrolysis for 6h completely removed arabinose (Ara), partial galactose (Gal), but little GalA and Rha. During partial hydrolysis, the molecular weight of WGPA-2-RG decreased smoothly, suggesting that the Ara and cleavable Gal residues exist on the surface of the molecule, while GalA and Rha residues exist in the core of the molecule. The bioactivity assay showed that the arabinogalactan side chains of WGPA-2-RG are essential structures for stimulating NO secretion and lymphocyte proliferation. However, removal of the Ara and Gal residues through hydrolysis did not appreciably affect the ability of WGPA-2-RG to enhance macrophage phagocytosis.

Topics: Animals; Cell Proliferation; Hydrolysis; Lymphocytes; Macrophages, Peritoneal; Methylation; Mice; Neutral Red; Oxidation-Reduction; Panax; Pectins; Periodic Acid; Phagocytosis; Spleen; Trifluoroacetic Acid

An ultrasensitive electrical detection method of nucleic acids has been developed on a nanogapped biosensor. In this study, peptide nucleic acid (PNA) probes were immobilized in the gaps of a pair of finger microelectrodes first and were then hybridized with their complementary target DNA. After that, pectin molecules were introduced into the DNA strand via zirconium-phosphate and zirconium-carbonate chemistries and were oxidated by periodate in acetate buffer (pH 3.98). The newly produced aldedyde groups act as a reactant to reduce ammoniacal silver ion to produce silver nanoparticles, which bridged the gap of the interdigitated microelectrode. The conductance of the metallic nanoparticles correlated directly with the amount of the hybridized DNA. A much higher sensitivity was achieved at 3 femtomolar (S/N > 3) under optimal conditions. This biosensor is also applicable to the direct detection of RNA.

Topics: Biosensing Techniques; DNA; Electrochemistry; Models, Molecular; Nanowires; Oligonucleotide Probes; Pectins; Peptide Nucleic Acids; Periodic Acid; Polysaccharides; RNA; Sensitivity and Specificity; Silver; Zirconium