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13 C‐NMR Spectroscopic Detection of Malto‐oligosaccharide Complexes
Author(s) -
Vetter Dirk,
Thorn Werner
Publication year - 1992
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19920440708
Subject(s) - amylose , chemistry , glycosidic bond , degree of polymerization , nuclear magnetic resonance spectroscopy , crystallography , size exclusion chromatography , oligosaccharide , polymerization , proton nmr , spectroscopy , helix (gastropod) , carbon 13 nmr , stereochemistry , organic chemistry , polymer , ecology , physics , quantum mechanics , starch , snail , enzyme , biology
Fragments of amylose were enzymatically synthesized and purified to α‐(a→4)‐glucans of well defined degress of polymerization by preparative size exclusion chromatography. Maltooligosaccharides from DP 3 to 12 were subjected to 13 C‐NMR‐spectroscopy. The addition of iodine as a complexing agent selectively affected the carbon atoms involved in the glycosidic bond. Resonances of C‐1 and C‐4 experienced a dramatic downfield shift. This is interpreted as a change of conformation of the amylose helix. The shift differences can be measured conveniently and be used for calculations of complex stability constants. Maltohexaose and higher saccharides gave strong effects upon complexation, indicating that one helical turn brings about a gain in helical stability. No lower chain‐length limit for the complex‐forming capacity was observed. Even the smallest fragments of amylose showed complexing behaviour.