Document Detail


Synthesis and characterization of 2,3-di-O-alkylated amyloses: hydrophobic substitution destabilizes helical conformation.
MedLine Citation:
PMID:  12833257     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Amylose was selectively alkylated in the 2,3-O position of each anhydroglucose unit after trityl protection of the 6-OH groups. Alkyl iodides of varying chain length (C(2), C(5), C(8)) were coupled to amylose, and degrees of substitution (DSs) were varied between 0.3 and 1.8, as assessed by NMR analysis. Increasing amounts of methyl groups per anhydroglucose unit increased solubility in nonaqueous media, while at the same time reducing the ability of modified amylose to form a complex with iodine. The tendency to form inclusion complexes with the surfactant N-dodecyl pyridinium bromide decreased in the order beta-cyclodextrin >> amylose approximately solubilized starch, indicating that the frozen macrocycle of beta-cyclodextrin was the most efficient inclusion host. Introduction of the bulky trityl group abolished the helical amylose conformation, which is not readily reassumed in the presence of hydrophobic substitution of the C2 and C3 positions. These results indicated that a polar outer surface is necessary but not sufficient for the formation of a stable amylose helix.
Authors:
Hans-Georg Breitinger
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biopolymers     Volume:  69     ISSN:  0006-3525     ISO Abbreviation:  Biopolymers     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-06-30     Completed Date:  2004-09-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372525     Medline TA:  Biopolymers     Country:  United States    
Other Details:
Languages:  eng     Pagination:  301-10     Citation Subset:  IM    
Copyright Information:
Copyright 2003 Wiley Periodicals, Inc. Biopolymers 69: 301-310, 2003
Affiliation:
Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf. hgb@biochem.uni-erlangen.de
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MeSH Terms
Descriptor/Qualifier:
Alkylation
Amylose / chemical synthesis*,  chemistry*,  isolation & purification
Carbohydrate Conformation
Circular Dichroism
Hydrophobicity
Iodine / chemistry
Pliability
Solubility
Chemical
Reg. No./Substance:
7553-56-2/Iodine; 9005-82-7/Amylose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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