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13 C‐NMR relaxation in glycogen
Author(s) -
Overloop Kristen,
Vanstapel Florent,
Van Hecke Paul
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910360109
Subject(s) - relaxation (psychology) , chemistry , nuclear magnetic resonance , glycogen , t2 relaxation , viscosity , nuclear magnetic resonance spectroscopy , thermodynamics , physics , magnetic resonance imaging , biochemistry , medicine , psychology , social psychology , radiology
This study is the first report on the multiexponential T 2 relaxation of the 13 C‐1 carbon of glycogen. In contrast to T 1 relaxation, which does not display observable multiexponential decay behavior, T 2 relaxation is described by a continuous distribution of T 2 times. Changes in molecular weight and sample viscosity, which affect the overall mobility of the glycogen particle have little influence on T 1 and T 2 relaxation times. This is in contradiction with earlier results that T 2 is dominated by the overall motion of the glycogen particles [L.‐H. Zang Biochemistry 29, 6815–6820 (1990)]. T 1 depends strongly on the external field B o and is almost temperature independent in the range 23–37°C whereas T 2 is field independent and varies appreciably with temperature. The experimental T 1 and T 2 relaxation data are shown to be consistent with existing theoretical models for relaxation, suitably modified to include a distribution of correlation times for the internal motions. The presence of fast decaying components (short T 2 ) in the FID implies broad line components in the frequency spectrum and the corresponding need to appropriately set the integration limits for the quantification of the glycogen peak.