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Abstract: Effective degradation of compounds containing peptides or phosphate ester bonds in environment is important. In this paper complexes of algae polysaccharides (APS) and Ce4+ were made, and catalysts of the complexes for degradation of compounds containing peptides or phosphate ester bonds were examined. The results show that the complexes could hydrolyze bovine serum albumin (BSA). The complex composed of laminaran and Ce4+ could not only significantly hydrolyze BSA but also rapidly convert the supercoil DNA (plasmid DNA form) into the linear form DNA (plasmid DNA form) in neutral pH solution. They could also promote the degradation of chlorpyrifos. The chlorpyrifos residual in neutral pH solution treated by the complex was 1.16mg/l and the degradation rate was about 94.28% after 48h, whereas without the complex treatment the residual 9.37mg/l and the ration 53.82%. The chlorpyrifos residual in spinach from the treatment plot was only1.14mg/kg on 10 days after spraying the complex, whereas the residual in spinach from the control plot was 3.10mg/kg. [Copyright &y& Elsevier]

Short-chain glucan (SCG) derived from debranched amylopectin has emerged as a promising candidate for the production of resistant starch particle (RSP) due to its controllable self-assembly features. Here, we investigated the effect of metal cations with different valencies and concentrations on the morphology, physicochemical properties, and digestibility of RSP formed by the self-assembly of SCG. The effect of cations on the formation of RSP followed the valency in the following order: Na+, Ka+, Mg2+, Ca2+, Fe3+, and Al3+, of which 10 mM trivalent cations increased the particle size of RSP over 2 μm and considerably decreased the crystallinity by 49.5 % ~ 50.9 %, which were significantly different from that of mono- and divalent ones. Importantly, RSP formed with divalent cations switched the surface charge from −18.6 mV to 12.9 mV, which significantly increased the RS level, indicating that metal cations would be useful for regulating physicochemical properties and digestibility of RSP. [Display omitted] [ABSTRACT FROM AUTHOR]

The occurrence of enzymatic activities is attributed to proper spatial organization of functional groups from first principles. A novel chitosan-based Ce(IV) complex (CC[Ce(IV)]), an artificial metalloproteinase, was synthesized by attaching cyclen, Ce(IV), and chlorophyll–Cu(II) to a chitosan-based matrix. The enzymatic hydrolytic efficiency (HE) and the procedure of catalyzing myoglobin (Mb) by CC[Ce(IV)] in vitro were investigated using spectrophotometry, electrophoresis, and liquid chromatography. The results showed that the HE of Mb was up to 60% at 60 °C within 24 h, displaying a catalytic proficiency. The pseudo-first-order kinetic constant ( k obs ) for CC[Ce(IV)] treatment within 24 h was 3.85 × 10 −2 h −1 , higher than that for α-chymotrypsin treatment, which was 2.63 × 10 −2 h −1 . Moreover, the peptide bond derived from Asp-Phe/Phe-Asp in Mb could be specifically cleaved by CC[Ce(IV)], which could simulate the functionality of α-chymotrypsin. This work provides an experimental basis for potential utilization of the chitosan-based Ce(IV) complexes in the food industry. [ABSTRACT FROM AUTHOR]

Using d-glucosamine hydrochloride (GlcNH2·HCl) as starting material, a new amino acid sugar conjugate, arginine–glucosamine (Arg–GlcNH2), was synthesized and characterized by infrared spectroscopy, 13C NMR and element analysis. Its cytotoxicity in vitro was evaluated by MTT assay. The inhibition ratio against human hepatoma cell SMMC-7721 was higher than that of GlcNH2·HCl. This effect was accompanied by a marked increase in the proportion of S cells as analyzed by flow cytometry. In addition, SMMC-7721 cells treated with Arg–GlcNH2 resulted in the induction of apoptosis as assayed qualitatively by agarose gel electrophoresis. The manner of Arg–GlcNH2 cytocidal activity was concluded to be apoptosis. [Copyright &y& Elsevier]