DEUTERIUM ISOTOPE EFFECTS ON HYDROGEN BONDING

1966 ◽  
Vol 44 (22) ◽  
pp. 2611-2615 ◽  
Author(s):  
Surjit Singh ◽  
C. N. R. Rao
Keyword(s):  
Hydrogen Bonding ◽  
Isotope Effects ◽  
Equilibrium Constants ◽  
Zero Point ◽  
Deuterium Isotope Effects

The interaction of phenol and phenol-d with a number of donors of varying basicity has been studied in terms of the equilibrium constants, ΔS0, ΔH0, ΔvOH, and ΔvOD and various aspects of deuterium isotope effects on hydrogen bonding have been discussed. The deuterium isotope effects are found to vary markedly with the basicity of the donor and the results are discussed in terms of the zero point contributions to the KH/KD.

scholarly journals Unusual origins of isotope effects in enzyme-catalysed reactions

2006 ◽  
Vol 361 (1472) ◽  
pp. 1341-1349 ◽  
Author(s):  
Dexter B Northrop
Keyword(s):  
High Pressure ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Zero Point ◽  
Protein Domain ◽  
Enzymatic Reactions ◽  
Volume Changes ◽  
Mass Unit ◽  
Deuterium Isotope Effects ◽  
Domain Motions

High hydrostatic pressure is a neglected tool for probing the origins of isotope effects. In chemical reactions, normal primary deuterium isotope effects (DIEs) arising solely from differences in zero point energies are unaffected by pressure; but some anomalous isotope effects in which hydrogen tunnelling is suspected are partially suppressed. In some enzymatic reactions, high pressure completely suppresses the DIE. We have now measured the effects of high pressure on the parallel 13 C heavy atom isotope effect of yeast alcohol dehydrogenase and found that it is also suppressed by high pressure and, similarly, suppressed in its entirety. Moreover, the volume changes associated with the suppression of both deuterium and heavy atom isotope effects are virtually identical. The equivalent decrease in activation volumes for hydride transfer, when one mass unit is added to the carbon end of a scissile C–H bond as when one mass unit is added to the hydrogen end, suggests a common origin. Given that carbon is highly unlikely to undergo tunnelling, it follows that hydrogen is not doing so either. The origin of these isotope effects must lie elsewhere. We offer protein domain motions as a possibility.

Intramolecular hydrogen bonding of novelo-hydroxythioacetophenones and related compounds evaluated by deuterium isotope effects on13C chemical shifts

2007 ◽  
Vol 45 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Trung Thanh Nguyen ◽  
Thach Ngoc Le ◽  
Fritz Duus ◽  
Bjarke K. V. Hansen ◽  
Poul Erik Hansen
Keyword(s):  
Hydrogen Bonding ◽  
Chemical Shifts ◽  
Isotope Effects ◽  
Intramolecular Hydrogen Bonding ◽  
Deuterium Isotope Effects ◽  
Intramolecular Hydrogen ◽  
Related Compounds

Primary and secondary deuterium isotope effects on equilibrium constants for enzyme-catalyzed reactions

Biochemistry ◽  
1980 ◽  
Vol 19 (21) ◽  
pp. 4853-4858 ◽  
Author(s):  
Paul F. Cook ◽  
John S. Blanchard ◽  
W. W. Cleland
Keyword(s):  
Isotope Effects ◽  
Equilibrium Constants ◽  
Deuterium Isotope Effects ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions
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