2005 Fiscal Year Final Research Report Summary
Modeling of the 3D structure of the cluster of amylopectin
| Project/Area Number |
15580082
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied biochemistry
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| Research Institution | Kagoshima University |
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Principal Investigator |
HANASHIRO Isao Kagoshima University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (30336325)
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| Project Period (FY) |
2003 – 2005
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| Keywords | starch / amylopectin / cluster / fluorescent labeling |
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| Research Abstract |
For modeling of branched structure of amylopectin, analytical methods have been developed to gain insights to the branched structure.
1.Various conditions for determination of molecular- weight distribution of amylopectin were examined using HPSEC system equipped with a differential refractometer and a fluorescent detector. Amylopectin was separated into two major fractions based on the fluorescence detection while eluted as a single peak by detection with refractive index.
2.A method was established for determination of chain-length distribution of β-amylase limit dextrin (β-LD) of amylopectin. The method revealed that the distributions of various amylopectins were characteristic by their botanical sources. The results also suggested relationship between the chain-length distribution and x-ray diffraction patterns of starch granules. Successive hydrolysis of amylopectin with phosphorylase and β-amylase was attempted for preparation of corresponding limit dextrin (Φ,β-LD), which was then subjected to determination of chain-length distribution. The results obtained with Φ,β-LD were consistent with those with β-LD, that is, branched structure of amylopectin is related to starch granules' crystalline structure.
3.Models of branched structures of amylopectins from starches of A- and B-type crystalline were constructed, based on the information obtained in this study, such as number of side chains per a given unit-chains, internal chain-length, interval between two branch points. Respective model for A- or B-type showed distinct features in terms of branching in a cluster structure, indicating that the branching characteristics within a cluster unit, as well as average chain-length of the unit, have influence on determination of the higher-order, crystalline structure.
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