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Hydrolyzed Products (hydrolyzed + products)
Selected AbstractsCharacterization and solution properties of a partially hydrolyzed graft copolymer of polyacrylamide and dextranJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008S. Krishnamoorthi Abstract Graft copolymers of dextran (Dx) and polyacrylamide (PAM) were synthesized through the grafting of PAM chains onto a Dx backbone with a ceric-ion-induced solution polymerization technique. By the variation of the amount of the initiator (ceric ammonium nitrate), four different grades of graft copolymers were synthesized. The partial alkaline hydrolysis of Dx- g -PAM was carried out in an alkaline medium. Three grades of partially hydrolyzed products were synthesized through the variation of the amount of alkali. These hydrolyzed graft copolymers were characterized with elemental analysis, infrared spectroscopy, neutralization equivalent measurements, a rheological technique, scanning electron microscopy, thermal analysis, viscometry, and X-ray diffraction. The flocculation efficiency and viscosifying characteristics of the graft copolymers were enhanced upon their alkaline hydrolysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008. [source] FREE RADICAL-SCAVENGING ACTIVITIES OF LOW MOLECULAR WEIGHT CHITIN OLIGOSACCHARIDES LEAD TO ANTIOXIDANT EFFECT IN LIVE CELLSJOURNAL OF FOOD BIOCHEMISTRY, Issue 2010DAI-NGHIEP NGO ABSTRACT Chitin oligosaccharides (NA-COS) with low molecular weight distribution of 229.21,593.12 Da were produced from crab chitin by acid hydrolysis. They showed reducing power and scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) (Sigma Chemical Co., St. Louis, MO), hydroxyl and alkyl radicals. It was observed that the radical-scavenging activity of NA-COS increased in a dose-dependent manner. Their IC50 values for DPPH, hydroxyl and alkyl radicals were 0.8, 1.75 and 1.14 mg/mL, respectively. Furthermore, NA-COS exhibited the inhibitory effect on the oxidative damage of DNA from human lymphoma U937 (American Type Culture Collection, Manassas, VA) and the direct radical-scavenging effect in human fibrosarcoma cells (HT1080) (American Type Culture Collection) in 2,,7,-dichlorofluorescin diacetate (DCFH-DA) assay (Molecular Probes Inc., Eugene, OR). The results suggest that NA-COS can exert antioxidant effect in live cells and have the potential to be applied to food supplements or nutraceuticals. PRACTICAL APPLICATIONS Chitin oligosaccharides (NA-COS) are the hydrolyzed products of chitin (KEUMHO chemical products Co. Ltd., Gyeongbuk, Korea) of which derivatives have shown antioxidant, antimicrobial, anticancer, anti-inflammatory and immunostimulant effects. According to previous studies, NA-COS have beneficial biological activities similar to those of chitin. Furthermore, they are easily soluble in water because of their shorter chain length. Therefore, NA-COS are potentially applicable to improve food quality and human health. [source] Enzymatic Hydrolysis of , - and , -Oligo(L -aspartic acid)s by Poly(aspartic acid) Hydrolases-1 and 2 from Sphingomonas sp.MACROMOLECULAR BIOSCIENCE, Issue 3 2004Abstract Summary: The enzymatic hydrolysis of , - and , -oligo(L -aspartic acid)s by PAA hydrolase-1 and PAA hydrolase-2 (purified from Sphingomonas sp. KT-1) was performed to elucidate the mechanism of the microbial degradation by Sphingomonas sp. KT-1 of the thermally synthesized ,,, -poly(D,L -aspartic acid) (tPAA). GPC analysis of the hydrolyzed products of , - and , -tetra(L -aspartic acid)s by PAA hydrolase-1 has showed that PAA hydrolase-1 is capable of hydrolyzing only the specific amide bonds between , -aspartic acid units. The RP-HPLC analysis of the enzymatic hydrolysis of , -oligo(L -aspartic acid)s (4 and 5 mers) by PAA hydrolase-1 has suggested that the enzymatic hydrolysis of , -oligo(L -aspartic acid)s occurs via an endo-mode cleavage. In contrast, PAA hydrolase-2 hydrolyzed both , - and , -oligo(L -aspartic acid)s via an exo-mode cleavage to yield L -aspartic acid as a final product. A kinetic study on the enzymatic hydrolysis of , -oligo(L -aspartic acid)s (3 to 7 mers) by PAA hydrolase-2 has indicated that Km values are almost independent of the number of monomer units in oligomers of 4 to 7 mers, while that Vmax values are markedly dependent on the chain length and show a maximum value at 5 mer. A proposed mechanism of the enzymatic hydrolysis of tPAA by PAA hydrolase-1 and PAA hydrolase-2 in the cell of Sphingomonas sp. KT-1. [source] 31P Solid state NMR study of structure and chemical stability of dichlorotriphenylphosphoraneMAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2009Nina C. Gonnella Abstract Solid state 31P NMR spectroscopy was used to examine, monitor and quantify the compound integrity of the chemical reagent dichlorotriphenylphosphorane. Comparison was also made with solution 31P NMR spectra which showed that this highly reactive species could be observed in dry benzene prior to conversion to the hydrolyzed product. This is the first reported solid state NMR study of the stability and reactivity of dichlorotriphenylphosphorane and the first account of its observation and comparison in the solution state. In the solid state, the ionic and covalent forms for dichlorotriphenylphosphorane were observed along with hydrolyzed products, however, the degree of hydrolysis was dependent upon the rotor packing conditions. Calculation of the relative percent composition of dichlorotriphenylphosphorane with hydrolyzed product was made for samples prepared in air versus under nitrogen atmosphere. This information was critical in adjusting the amount of reagent used in chemical development syntheses and scale up laboratories. All hydrolyzed products were identified, based upon chemical comparisons with spectra of pure materials. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||