The kinetic equations for isotopic exchange reactions allowing for the presence of an isotope effect

1994 ◽  
Vol 53 (1) ◽  
pp. 123-129
Author(s):  
S. R. Logan ◽  
G. P. Shannon
Keyword(s):  
Isotope Effect ◽  
Isotopic Exchange ◽  
Kinetic Equations ◽  
Exchange Reactions

scholarly journals SECONDARY DEUTERIUM ISOTOPE EFFECT IN CHLORINE ISOTOPIC EXCHANGE REACTIONS IN ACETONITRILE

1972 ◽  
Vol 1 (12) ◽  
pp. 1223-1224 ◽  
Author(s):  
Nobuo Tanaka ◽  
Aritsune Kaji ◽  
Jun-ichi Hayami
Keyword(s):  
Isotope Effect ◽  
Isotopic Exchange ◽  
Exchange Reactions ◽  
Deuterium Isotope Effect

scholarly journals Ion-Pair Reactivity in Isotopic Exchange Reactions. I. Lithium Chloride in Acetone as Solvent.

1969 ◽  
Vol 23 ◽  
pp. 1175-1180 ◽  
Author(s):  
Per Beronius ◽  
Veikko Konttinen ◽  
G. Hagen ◽  
P. H. Nielsen ◽  
Alf A. Lindberg ◽  
...  
Keyword(s):  
Lithium Chloride ◽  
Isotopic Exchange ◽  
Ion Pair ◽  
Exchange Reactions

scholarly journals Fast Isotopic Exchange between Mitochondria and Cytosol in Brain Revealed by Relayed 13C Magnetization Transfer Spectroscopy

2009 ◽  
Vol 29 (4) ◽  
pp. 661-669 ◽  
Author(s):  
Jehoon Yang ◽  
Su Xu ◽  
Jun Shen
Keyword(s):  
Isotopic Exchange ◽  
Tricarboxylic Acid Cycle ◽  
Magnetization Transfer ◽  
Tricarboxylic Acid ◽  
Transfer Effect ◽  
Resonance Spectroscopy ◽  
Exchange Reactions ◽  
Acid Cycle ◽  
Longitudinal Relaxation

In vivo13C magnetic resonance spectroscopy has been applied to studying brain metabolic processes by measuring 13C label incorporation into cytosolic pools such as glutamate and aspartate. However, the rate of exchange between mitochondrial α-ketoglutarate/oxaloacetate and cytosolic glutamate/aspartate ( Vx) extracted from metabolic modeling has been controversial. Because brain fumarase is exclusively located in the mitochondria, and mitochondrial fumarate is connected to cytosolic aspartate through a chain of fast exchange reactions, it is possible to directly measure Vx from the four-carbon side of the tricarboxylic acid cycle by magnetization transfer. In isoflurane-anesthetized adult rat brain, a relayed 13C magnetization transfer effect on cytosolic aspartate C2 at 53.2ppm was detected after extensive signal averaging with fumarate C2 at 136.1ppm irradiated using selective radiofrequency pulses. Quantitative analysis using Bloch–McConnell equations and a four-site exchange model found that VxE13–19 µmol per g per min (≫ VTCA, the tricarboxylic acid cycle rate) when the longitudinal relaxation time of malate C2 was assumed to be within ±33% of that of aspartate C2. If VxE VTCA, the isotopic exchange between mitochondria and cytosol would be too slow on the time scale of 13C longitudinal relaxation to cause a detectable magnetization transfer effect.

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