Fine structural properties of natural and synthetic glycogens

Takata, Hitoshi; Kajiura, Hideki; Furuyashiki, Takashi; Kakutani, Ryo; Kuriki, Takashi

doi:10.1016/j.carres.2009.01.008

Cited by 56 publications

(70 citation statements)

References 16 publications

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“…The values of M n and M w =M n of the glycogen reagent were reported in previous literature to be 4.9 Â 10 6 and 1.2, respectively. [16] Other regents were used as received. An ESA sample was prepared by the phosphorylase-catalyzed polymerization of Glc-1-P using maltoheptaose as a primer.…”

Section: Experimental Part Materialsmentioning

confidence: 99%

Preparation of Glycogen‐Based Polysaccharide Materials by Phosphorylase‐Catalyzed Chain Elongation of Glycogen

Izawa

Nawaji

Kaneko

et al. 2009

Macromolecular Bioscience

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Facile preparation of glycogen-based polysaccharide gel materials was carried out by phosphorylase-catalyzed chain elongation of glycogen using glucose 1-phosphate (Glc-1-P). The resulting solution after the enzymatic reaction gradually turned into a hydrogel form, which was probably caused by formation of junction zones based on the double helix structure of the elongated amylose chains among the glycogen molecules. Furthermore, lyophilization of the hydrogel resulted in formation of a glycogen-based xerogel. The mechanical properties of the hydrogels and xerogels were affected by the amount of glycogen and the Glc-1-P/glycogen ratio in the feed for the enzymatic reaction. The xerogel was also subjected to film formation and re-hydrogelation with appropriate techniques.

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Section: Experimental Part Materialsmentioning

confidence: 99%

Preparation of Glycogen‐Based Polysaccharide Materials by Phosphorylase‐Catalyzed Chain Elongation of Glycogen

Izawa

Nawaji

Kaneko

et al. 2009

Macromolecular Bioscience

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“…The average chain lengths of ESGs (A-I) tended to be slightly shorter than those of NSGs, whereas exterior chain lengths and interior chain lengths were within the variations of the values for NSGs (Table 2). On the other hand, the unit-chain distributions of ESGs and NSGs as analyzed by high-performance anion exchange chromatography after IAM treatment were slightly different from each other (Takata et al 2009): NSGs have larger amounts of long unit chains (degree of polymerization (DP): 25- …”

Section: Structures Of Esgmentioning

confidence: 93%

“…Furthermore, we tested the susceptibility of ESG by excess amounts of α-amylase (Takata et al 2009). The final products of α-amylase hydrolysis of NSG were glucose, maltose, maltotriose, branched oligosaccharides with DP≥4, and highly branched macrodextrin molecules with molecular weights of up to 10 k. In the final products of α- a Reducing sugars were measured by the dinitrosalicylic acid method (Takata et al 2009). amylase hydrolysis of ESGs, we detected much larger macrodextrins (molecular weight >1,000 k).…”

Section: Susceptibility Of Esg To Pullulanase and α-Amylasementioning

confidence: 99%

In vitro synthesis of glycogen: the structure, properties, and physiological function of enzymatically-synthesized glycogen

et al. 2011

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This review describes a new enzymatic method for in vitro glycogen synthesis and its structure and properties. In this method, short-chain amylose is used as the substrate for branching enzymes (BE, EC 2.4.1.18). Although a kidney bean BE and Bacillus cereus BE could not synthesize high-molecular weight glucan, BEs from 6 other bacterial sources produced enzymatically synthesized glycogen (ESG). The BE from Aquifex aeolicus was the most suitable for the production of glycogen with a weight-average molecular weight (Mw) of 3,000-30,000 k. The molecular weight of the ESG is controllable by changing the concentration of the substrate amylose. Furthermore, the addition of amylomaltase (AM, EC 2.4.1.25) significantly enhanced the efficiency of this process, and the yield of ESG reached approximately 65%. Typical preparations of ESG obtained by this method were subjected to structural analyses. The average chain length, interior chain length, and exterior chain length of the ESGs were 8.2-11.6, 2.0-3.3, and 4.2-7.6, respectively. Transmission electron microscopy and intrinsic viscosity measurement showed that the ESG molecules formed spherical particles. Unlike starch, the ESGs were barely degraded by pullulanase. Solutions of ESG were opalescent (milky-white and slightly bluish), and gave a reddishbrown color on the addition of iodine. These analyses revealed that ESG shares similar molecular shapes and solution properties with natural-source glycogen. Moreover, ESG had macrophage-stimulating activity and its activity depends on the molecular weight of ESG. We successfully achieved large scale production of ESG. ESG could lead to new industrial applications, such as in the food, chemical, and pharmaceutical fields.

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“…There have however been several encouraging studies using aqueous SEC to characterise synthetic and commercial glycogen. [9,11,34,35] There are several other advantages to using an aqueous system: water is cheaper, safer, easier to dispose of and more physiologically relevant than DMSO. The universal calibration assumption was used here.…”

Section: Glycogen Size Characterisationmentioning

confidence: 99%

The Molecular Size Distribution of Glycogen and its Relevance to Diabetes

Gilbert

Sullivan

2014

Aust. J. Chem.

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Glycogen is a highly branched polymer of glucose, functioning as a blood-glucose buffer. It comprises relatively small b-particles, which may be joined as larger aggregate a-particles. The size distributions from size-exclusion chromatography (SEC, also known as GPC) of liver glycogen from non-diabetic and diabetic mice show that diabetic mice have impaired a-particle formation, shedding new light on diabetes. SEC data also suggest the type of bonding holding b-particles together in a-particles. SEC characterisation of liver glycogen at various time points in a day/night cycle indicates that liver glycogen is initially synthesised as b-particles, and then joined by an unknown process to form a-particles. These a-particles are more resistant to degradation, presumably because of their lower surface area-to-volume ratio. These findings have important implications for new drug targets for diabetes management.

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Fine structural properties of natural and synthetic glycogens

Cited by 56 publications

References 16 publications

Preparation of Glycogen‐Based Polysaccharide Materials by Phosphorylase‐Catalyzed Chain Elongation of Glycogen

Preparation of Glycogen‐Based Polysaccharide Materials by Phosphorylase‐Catalyzed Chain Elongation of Glycogen

In vitro synthesis of glycogen: the structure, properties, and physiological function of enzymatically-synthesized glycogen

The Molecular Size Distribution of Glycogen and its Relevance to Diabetes

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