17750-30-0Relevant articles and documents
Deuterium Isotope Effects for the Nonenzymatic and Glutamate Dehydrogenase Catalyzed Reduction of an α-Imino Acid by NADH
Srinivasan, R.,Fisher, Harvey F.
, p. 4301 - 4305 (1985)
The mechanisms of the nonenzymatic and glutamate dehydrogenase catalyzed reduction of an α-imino acid, Δ1-pyrroline-2-carboxylic acid, by NAD(P)H have been studied by deuterium isotope effects.The partition isotope effects for the nonenzymatic reaction with 4-deuterated 1,4-dihydronicotinamides are about the same as the corresponding observed kinetic isotope effects with 4,4-dideuterio-1,4-dihydronicotinamides, suggesting that the hydrogen-transfer step is solely rate limiting.This reaction is characterized by an intrinsic primary kinetic isotope effect of 1.3 and a very product-like transition state.The enzymatic reaction has been studied by determining the second-order rate constants for the reduction of the imino acid by the enzyme-NADH complex with 4,4-dideuterio and stereospecifically labeled 4-deuterio NADH.The primary isotope effect when the in-place hydrogen is protium is 3.80, and the secondary isotope effect when the in-flight hydrogen is protium is 1.21.Deuteration at one site lowers the isotope effects at the other by 13percent.The following conclusions emerge for the reduction of the imino acid by the enzyme-NADH complex: (1) the hydrogen-transfer step is at least rate contributing, (2) the transition state for this reaction is more symmetric than that of the nonenzymatic reaction, (3) both the C-4 hydrogens of NADH participate in the reaction coordinate motion, and (4) there is some nuclear tunneling in the reaction coordinate.The kinetic isotope effect for the oxidation of proline and proline-2-d by enzyme-NADP(+) is 4.1.
Regioselective reduction of NAD+ models with [Cp*Rh(bpy)H]+: Structure-activity relationships and mechanistic aspects in the formation of the 1,4-NADH derivatives
Lo, H. Christine,Buriez, Olivier,Kerr, John B.,Fish, Richard H.
, p. 1429 - 1432 (1999)
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Donor-Acceptor Distance Sampling Enhances the Performance of "better than Nature" Nicotinamide Coenzyme Biomimetics
Geddes, Alexander,Paul, Caroline E.,Hay, Sam,Hollmann, Frank,Scrutton, Nigel S.
supporting information, p. 11089 - 11092 (2016/10/23)
Understanding the mechanisms of enzymatic hydride transfer with nicotinamide coenzyme biomimetics (NCBs) is critical to enhancing the performance of nicotinamide coenzyme-dependent biocatalysts. Here the temperature dependence of kinetic isotope effects (