Nuclear quantum effects in enzymatic reactions: simulation of the kinetic isotope effect of phenylethylamine oxidation catalyzed by monoamine oxidase A

2020 ◽  
Vol 22 (13) ◽  
pp. 6838-6847 ◽  
Author(s):  
Alja Prah ◽  
Peter Ogrin ◽  
Janez Mavri ◽  
Jernej Stare

By using computational techniques for quantizing nuclear motion one can accurately reproduce kinetic isotope effect of enzymatic reactions, as demonstrated for phenylethylamine oxidation catalyzed by the monoamine oxidase A enzyme.

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4359 ◽  
Author(s):  
Mateusz Z. Brela ◽  
Alja Prah ◽  
Marek Boczar ◽  
Jernej Stare ◽  
Janez Mavri

Monoamine oxidase A (MAO A) is a well-known enzyme responsible for the oxidative deamination of several important monoaminergic neurotransmitters. The rate-limiting step of amine decomposition is hydride anion transfer from the substrate α–CH2 group to the N5 atom of the flavin cofactor moiety. In this work, we focus on MAO A-catalyzed benzylamine decomposition in order to elucidate nuclear quantum effects through the calculation of the hydrogen/deuterium (H/D) kinetic isotope effect. The rate-limiting step of the reaction was simulated using a multiscale approach at the empirical valence bond (EVB) level. We applied path integral quantization using the quantum classical path method (QCP) for the substrate benzylamine as well as the MAO cofactor flavin adenine dinucleotide. The calculated H/D kinetic isotope effect of 6.5 ± 1.4 is in reasonable agreement with the available experimental values.


2019 ◽  
Vol 141 (34) ◽  
pp. 13635-13642 ◽  
Author(s):  
Lu Gem Gao ◽  
Rui Ming Zhang ◽  
Xuefei Xu ◽  
Donald G. Truhlar

2018 ◽  
Vol 9 (12) ◽  
pp. 3024-3027 ◽  
Author(s):  
Lindsey R. Drake ◽  
Allen F. Brooks ◽  
Anthony J. Mufarreh ◽  
Jonathan M. Pham ◽  
Robert A. Koeppe ◽  
...  

2019 ◽  
Vol 167 (1) ◽  
pp. 49-54
Author(s):  
Małgorzata Pająk

Abstract The isotope effects approach was used to elucidate the mechanism of oxidative deamination of 3′-halotyramines, catalyzed by monoamine oxidase A (EC 1.4.3.4). The numerical values of kinetic isotope effect (KIE) and solvent isotope effect (SIE) were established using a non-competitive spectrophotometric technique. Based upon KIE and SIE values, some of the mechanistic details of investigated reaction were discussed.


2020 ◽  
Vol 22 (20) ◽  
pp. 11219-11243 ◽  
Author(s):  
Ken Sakaushi

The fundamental aspects of quantum electrocatalysts are discussed together with the newly developed electrochemical kinetic isotope effect (EC-KIE) approach.


1993 ◽  
Vol 290 (1) ◽  
pp. 103-107 ◽  
Author(s):  
O Smékal ◽  
M Yasin ◽  
C A Fewson ◽  
G A Reid ◽  
S K Chapman

L-Lactate dehydrogenase (L-LDH) from Saccharomyces cerevisiae and L-mandelate dehydrogenase (L-MDH) from Rhodotorula graminis are both flavocytochromes b2. The kinetic properties of these enzymes have been compared using steady-state kinetic methods. The most striking difference between the two enzymes is found by comparing their substrate specificities. L-LDH and L-MDH have mutually exclusive primary substrates, i.e. the substrate for one enzyme is a potent competitive inhibitor for the other. Molecular-modelling studies on the known three-dimensional structure of S. cerevisiae L-LDH suggest that this enzyme is unable to catalyse the oxidation of L-mandelate because productive binding is impeded by steric interference, particularly between the side chain of Leu-230 and the phenyl ring of mandelate. Another major difference between L-LDH and L-MDH lies in the rate-determining step. For S. cerevisiae L-LDH, the major rate-determining step is proton abstraction at C-2 of lactate, as previously shown by the 2H kinetic-isotope effect. However, in R. graminis L-MDH the kinetic-isotope effect seen with DL-[2-2H]mandelate is only 1.1 +/- 0.1, clearly showing that proton abstraction at C-2 of mandelate is not rate-limiting. The fact that the rate-determining step is different indicates that the transition states in each of these enzymes must also be different.


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