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Novel enzyme-membrane reactor for polysaccharide synthesis

Enzyme-membrane reactor for polysaccharide synthesis, ..

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Detection of enzyme-catalyzed polysaccharide synthesis …

Perrin RM, Derocher AE, Bar‐Peled M et al. (1999) Xyloglucan fucosyltransferase, an enzyme involved in plant cell wall biosynthesis. Science 284: 1976–1979.

New developments of polysaccharide synthesis via enzymatic polymerization

This review focuses on the synthesis of polysaccharides, the method of which is “enzymatic polymerization” mainly developed by our group. Polysaccharides are formed by repeated glycosylation reactions between a glycosyl donor and a glycosyl acceptor. A hydrolysis enzyme was found very efficient as catalyst, where the monomer is designed based on the new concept of a “transition-state analogue substrate” (TSAS); sugar fluoride monomers for polycondensation and sugar oxazoline monomers for ring-opening polyaddition. Enzymatic polymerization enabled the first synthesis of natural polysaccharides such as cellulose, xylan, chitin, hyaluronan and chondroitin, and also of unnatural polysaccharides such as a cellulose–chitin hybrid, a hyaluronan–chondroitin hybrid, and others. Supercatalysis of hyaluronidase was disclosed as unusual enzymatic multi-catalyst functions. Mutant enzymes were very useful for synthetic and mechanistic studies. observations of enzymatic polymerization by SEM, TEM, and combined SAS methods revealed mechanisms of the polymerization and of the self-assembling of high-order molecular structure formed by elongating polysaccharide molecules.

(Communicated by Hitosi NOZAKI, M.J.A.)

(monosaccharide, disaccharide, polysaccharide, and oligosaccharide)

Oxidant-Induced Inhibition of Enzymes Involved in Cell Wall Polysaccharide Synthesis

N2 - Biochemical methods for demonstration of enzyme activity are test tube models outside the organization of cell. Their application to the complicated organization of the cell present problems to histochemistry. The morphological and chemical preservation of tissue which is desirable in histochemistry leads to a multiplicity of reactions when "test tube" methods are applied. For example, the histochemical phosphorylase and glycosyltransferase reactions rest on the assumption that one can distinguish between preexisting glycogen and newly formed polysaccharides. We used frozen dried canine myocardium and liver for examination of the authenticity of histochemical phosphorylase and glycosyltransferase (branching enzyme, UDPG-glycogen transglycosylase) reactions as described in histochemical reference books. We were unable to distinguish between preexisting glycogen and supposedly newly formed polysaccharides with methods presently used for this purpose (Iodine stain, differential digestion with amylases, acid hydrolysis). Tissue without PAS stainable glycogen remained so after substrate incubation. When preexisting glycogen was present, the amounts of stainable polysaccharides after incubation were invariably less. Therefore, we could not prove beyond doubt that any polysaccharide synthesis due to enzyme reaction had oceured. The prescribed controls, perhaps adequate for biochemical "test tube" reactions, have to be redefined for meaningful histochemical procedures.

Biochemical methods for demonstration of enzyme activity are test tube models outside the organization of cell. Their application to the complicated organization of the cell present problems to histochemistry. The morphological and chemical preservation of tissue which is desirable in histochemistry leads to a multiplicity of reactions when "test tube" methods are applied. For example, the histochemical phosphorylase and glycosyltransferase reactions rest on the assumption that one can distinguish between preexisting glycogen and newly formed polysaccharides. We used frozen dried canine myocardium and liver for examination of the authenticity of histochemical phosphorylase and glycosyltransferase (branching enzyme, UDPG-glycogen transglycosylase) reactions as described in histochemical reference books. We were unable to distinguish between preexisting glycogen and supposedly newly formed polysaccharides with methods presently used for this purpose (Iodine stain, differential digestion with amylases, acid hydrolysis). Tissue without PAS stainable glycogen remained so after substrate incubation. When preexisting glycogen was present, the amounts of stainable polysaccharides after incubation were invariably less. Therefore, we could not prove beyond doubt that any polysaccharide synthesis due to enzyme reaction had oceured. The prescribed controls, perhaps adequate for biochemical "test tube" reactions, have to be redefined for meaningful histochemical procedures.

polysaccharide chain-forming enzymes, ..

The carbohydrate unit so formed is then converted into the glycogen macromolecule by glycogen synthesizing enzymes.A new protein ..

Through their influence on plant cell wall polysaccharide structure, plant cell wall glycosyltransferases influence growth, development, cell division and environmental responses as well as plant‐derived food products, biofuels, textiles, paper and timber. Plant cell wall synthesizing enzymes can be processive (glycan synthases) or nonprocessive, and are integral membrane proteins with single or multiple transmembrane domains. Plant cell wall glycosyltransferases can be challenging to study biochemically, as they tend to be labile, present in multimeric complexes and encoded by large gene families whose members may have overlapping function. Candidate proteins may be identified by homology, but their function must be confirmed with biochemical evidence. Strategies for confirmation include expression in heterologous systems followed by assays of enzymatic activity or detection of carbohydrate products. Loss of function or gain‐of‐function techniques may be useful. Despite challenges, numerous plant cell wall glycosyltransferases have been identified; hundreds more, however, await further characterization.

T1 - Genetic and biochemical analyses of the Pseudomonas aeruginosa Psl exopolysaccharide reveal overlapping roles for polysaccharide synthesis enzymes in Psl and LPS production

Disaccharides are formed when two monosaccharides join together by the dehydration synthesis reaction resulting in a glycosidic bond …
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  • New development of polysaccharide synthesis via …

    Polysaccharide - Wikipedia

  • 19/12/2017 · New development of p..

    Areas discussed are a brief history of the Golgi polysaccharide synthesis in ..

  • recombinant enzymes and metabolic ..

    Synthesis of the variable, outermost O-polysaccharide part begins on the cytoplasmic face of the inner membrane with ..

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PDF Downloads : Oriental Journal of Chemistry

Robert S, Bichet A, Grandjean O et al. (2005) An Arabidopsis endo‐1,4‐beta‐d‐glucanase involved in cellulose synthesis undergoes regulated intracellular cycling. Plant Cell 17: 3378–3389.

Photochemical Synthesis of Gold Nanorods - Journal of …

Jensen JK, Sørensen SO, Harholt J et al. (2008) Identification of a xylogalacturonan xylosyltransferase involved in pectin biosynthesis in Arabidopsis. Plant Cell 20(5): 1289–1302.

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Faik A, Price NJ, Raikhel NV and Keegstra K (2002) An Arabidopsis gene encoding an alpha‐xylosyltransferase involved in xyloglucan biosynthesis. Proceedings of the National Academy of Sciences of the USA 99: 7797–7802.

Bacterial Biofilm: Its Composition, Formation and Role …

Egelund J, Petersen BL, Motawia MS et al. (2006) Arabidopsis thaliana RGXT1 and RGXT2 encode Golgi‐localized (1,3)‐alpha‐D‐xylosyltransferases involved in the synthesis of pectic rhamnogalacturonan II. Plant Cell 18: 2593–2607.

Muhsin Jamal *, Ufaq Tasneem, Tahir Hussain and Saadia Andleeb

Numerous enzymes involved in synthesis of plant cell wall biosynthesis have been identified. These include cellulose synthase, callose synthase, xyloglucan biosynthetic enzymes, pectin biosynthetic enzymes, mixed‐linkage glycan synthase and enzymes synthesizing mannans. However, many hundreds of enzymes remain to be identified at the biochemical level.

ALTERNATIVE MEDICINE APPROACHES TO DISEASE

With reagents in place, a final requirement was a suitable assay of Wzy activity. In the final step of the substrate synthesis, catalyzed by WbnI, a radioactive label was added to the pentasaccharide-PP-Und. After incubation with Wzy, analysis of the reaction products showed that up to 13 repeating units could be resolved, confirming that Wzy catalyzes polymerization of repeating units.

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