Online monitoring of the kinetic isotope effect in chemical reactions with 1H and 19F low-field NMR spectroscopy

The Analyst ◽  
2018 ◽  
Vol 143 (18) ◽  
pp. 4408-4421 ◽  
Author(s):  
Kawarpal Singh ◽  
Bernhard Blümich
Keyword(s):  
Nmr Spectroscopy ◽  
Real Time ◽  
Isotope Effect ◽  
Chemical Reactions ◽  
Kinetic Isotope Effect ◽  
Online Monitoring ◽  
Real Time Monitoring ◽  
Low Field ◽  
Kinetic Isotope ◽  
Low Field Nmr

Real-time monitoring of the kinetic isotope effect by low-field 1H and 19F spectroscopy.

Enhanced photocatalytic reduction of Cr(vi) to Cr(iii) over g-C3N4 catalysts with Ag nanoclusters in conjunction with Cr(iii) quantification based on operando low-field NMR relaxometry

2020 ◽  
Vol 7 (9) ◽  
pp. 2823-2832
Author(s):  
Xingxing Niu ◽  
Jingxian Dong ◽  
Xue Lu Wang ◽  
Ye-Feng Yao
Keyword(s):  
Real Time ◽  
Photocatalytic Reduction ◽  
Real Time Monitoring ◽  
Low Field ◽  
Nmr Relaxometry ◽  
Low Field Nmr ◽  
Ag Nanoclusters

Ag nanoclusters are anchored on g-C3N4 for the photocatalytic reduction of Cr(vi), and experience real-time monitoring by operando low-field NMR relaxometry via quantifying the concentration of paramagnetic Cr(iii) in solution.

Quantum electrocatalysts: theoretical picture, electrochemical kinetic isotope effect analysis, and conjecture to understand microscopic mechanisms

2020 ◽  
Vol 22 (20) ◽  
pp. 11219-11243 ◽  
Author(s):  
Ken Sakaushi
Keyword(s):  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Effect Analysis ◽  
Kinetic Isotope

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

scholarly journals l-mandelate dehydrogenase from Rhodotorula graminis: comparisons with the l-lactate dehydrogenase (flavocytochrome b2) from Saccharomyces cerevisiae

1993 ◽  
Vol 290 (1) ◽  
pp. 103-107 ◽  
Author(s):  
O Smékal ◽  
M Yasin ◽  
C A Fewson ◽  
G A Reid ◽  
S K Chapman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lactate Dehydrogenase ◽  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Dimensional Structure ◽  
Striking Difference ◽  
Kinetic Properties ◽  
Proton Abstraction ◽  
Rate Determining Step ◽  
Kinetic Isotope

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.

Sign in / Sign up

Export Citation Format

Share Document