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Difference between Extra‐ and Intracellular T 1 Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR
Author(s) -
Karlsson Magnus,
Jensen Pernille Rose,
ArdenkjærLarsen Jan Henrik,
Lerche Mathilde H.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201607535
Subject(s) - intracellular , chemistry , extracellular , carboxylic acid , kinetics , cytosol , intracellular ph , moiety , biophysics , biochemistry , stereochemistry , enzyme , biology , physics , quantum mechanics
Incomplete knowledge of the longitudinal relaxation time constant ( T 1 ) leads to incorrect assumptions in quantitative kinetic models of cellular systems, studied by hyperpolarized real‐time NMR. Using an assay that measures the intracellular signal of small carboxylic acids in living cells, the intracellular T 1 of the carboxylic acid moiety of acetate, keto‐isocaproate, pyruvate, and butyrate was determined. The intracellular T 1 is shown to be up to four‐fold shorter than the extracellular T 1 . Such a large difference in T 1 values between the inside and the outside of the cell has significant influence on the quantification of intracellular metabolic activity. It is expected that the significantly shorter T 1 value of the carboxylic moieties inside cells is a result of macromolecular crowding. An artificial cytosol has been prepared and applied to predict the T 1 of other carboxylic acids. We demonstrate the value of this prediction tool.