Publication Date:
2014-07-03
Description:
Purpose To introduce a direct method for estimating relaxation and kinetic parameter values from rapid dissolution dynamic nuclear polarization (RD-DNP) NMR time courses. Theory and Methods The analysis relied on a kinetic model that is often used to analyze data in these studies—a unidirectional (bio)chemical reaction with rate constant k 1 , coupled to longitudinal relaxation of the magnetization of substrate and product that is characterized by the time constant T 1 . The latter value was estimated from the width of the product curve (peak) at the height α relative to the maximum height. We showed α ∼ 0.8 under most conditions, so we measured the interval between the falling and rising parts of the curve at the relative height 0.8. We called this the “fall-minus-rise time at height α ,” or FmR α , and found that FmR 0.8 ∼ T 1 . The ratio β = (substrate signal/product signal) when the product is maximal was shown to be equal to k 1 T 1 . Therefore, k 1 = β/FmR 0.8 . Results FmR α analysis was demonstrated with 13 C NMR RD-DNP data recorded from hemolysates and from previously published data. Conclusion FmR α analysis enables immediate estimates of kinetic and relaxation parameters from 13 C NMR RD-DNP data. The values can be used as initial estimates in more extensive computer-based data-regression analysis. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
Print ISSN:
0740-3194
Electronic ISSN:
1522-2594
Topics:
Medicine
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