Difference between Extra- and Intracellular T1Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR.
Incomplete knowledge of the longitudinal relaxation time constant (T1) 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 T1of the carboxylic acid moiety of acetate, keto-isocaproate, pyruvate, and butyrate was determined. The intracellular T1is shown to be up to four-fold shorter than the extracellular T1. Such a large difference in T1values 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 T1value of the carboxylic moieties inside cells is a result of macromolecular crowding. An artificial cytosol has been prepared and applied to predict the T1of other carboxylic acids. We demonstrate the value of this prediction tool.
Technical University of Denmark, Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Building 349, DK-2800, Kgs Lyngby, Denmark.
Magnus
0000-0001-7738-1700
M
Karlsson
Technical University of Denmark, Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Building 349, DK-2800, Kgs Lyngby, Denmark.
Pernille Rose
0000-0003-4359-848X
PR
Jensen
Technical University of Denmark, Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Building 349, DK-2800, Kgs Lyngby, Denmark.
Jan Henrik
0000-0001-6167-6926
JH
Ardenkjaer-Larsen
Technical University of Denmark, Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Building 349, DK-2800, Kgs Lyngby, Denmark. mhauler@elektro.dtu.dk.
Mathilde H
0000-0002-5899-2781
MH
Lerche
D002264:Carboxylic Acids / Q000032:analysis* / Q000378:metabolism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism
D002264:Carboxylic Acids
NMR spectroscopy; carboxylic acids; dissolution DNP; hyperpolarization; longitudinal relaxation