Insights into transition state stabilization of the β-1,4-glycosidase Cex by covalent intermediate accumulation in active site mutants

10.1038/1852 ◽  
1998 ◽  
Vol 5 (9) ◽  
pp. 812-818 ◽  
Author(s):  
Valerie Notenboom ◽  
Camelia Birsan ◽  
Mark Nitz ◽  
David R. Rose ◽  
R. Antony J. Warren ◽  
...  
Keyword(s):  
Transition State ◽  
Active Site ◽  
Transition State Stabilization ◽  
Covalent Intermediate ◽  
Active Site Mutants

scholarly journals Inhibition of pancreatic lipase in vitro by the covalent inhibitor tetrahydrolipstatin

1988 ◽  
Vol 256 (2) ◽  
pp. 357-361 ◽  
Author(s):  
P Hadváry ◽  
H Lengsfeld ◽  
H Wolfer
Keyword(s):  
Transition State ◽  
Acid Derivative ◽  
Pancreatic Lipase ◽  
Active Site ◽  
Boronic Acid ◽  
Selective Inhibitor ◽  
Covalent Intermediate ◽  
State Form ◽  
Covalent Inhibitor

Tetrahydrolipstatin inhibits pancreatic lipase from several species, including man, with comparable potency. The lipase is progressively inactivated through the formation of a long-lived covalent intermediate, probably with a 1:1 stoichiometry. The lipase substrate triolein and also a boronic acid derivative, which is presumed to be a transition-state-form inhibitor, retard the rate of inactivation. Therefore, in all probability, tetrahydrolipstatin reacts with pancreatic lipase at, or near, the substrate binding or active site. Tetrahydrolipstatin is a selective inhibitor of lipase; other hydrolases tested were at least a thousand times less potently inhibited.

Functional tyrosine residue in the active center of human dipeptidyl peptidase III

2008 ◽  
Vol 389 (2) ◽  
pp. 163-167 ◽  
Author(s):  
Branka Salopek-Sondi ◽  
Bojana Vukelić ◽  
Jasminka Špoljarić ◽  
Šumski Šimaga ◽  
Dušica Vujaklija ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transition State ◽  
Active Site ◽  
Functional Role ◽  
Dipeptidyl Peptidase ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Tyrosine Residue ◽  
Transition State Stabilization ◽  
Endogenous Defense

Abstract Human dipeptidyl peptidase III (DPP III) is a member of the metallopeptidase family M49 with an implied role in the pain-modulatory system and endogenous defense against oxidative stress. Here, we report the heterologous expression of human DPP III and the site-directed mutagenesis results which demonstrate a functional role for Tyr318 at the active site of this enzyme. The substitution of Tyr318 to Phe decreased k cat by two orders of magnitude without altering the binding affinity of substrate, or of a competitive hydroxamate inhibitor designed to interact with S1 and S2 subsites. The results indicate that the conserved tyrosine could be involved in transition state stabilization during the catalytic action of M49 peptidases.

scholarly journals Visualization of the Differential Transition State Stabilization within the Active Site Environment

2004 ◽  
Vol 5 (4) ◽  
pp. 186-195 ◽  
Author(s):  
Pawel Kedzierski ◽  
Pawel Wielgus ◽  
Adrian Sikora ◽  
W. Sokalski ◽  
Jerzy Leszczynski
Keyword(s):  
Transition State ◽  
Active Site ◽  
Transition State Stabilization

scholarly journals 1-(3-Tert-Butylphenyl)-2,2,2-Trifluoroethanone as a Potent Transition-State Analogue Slow-Binding Inhibitor of Human Acetylcholinesterase: Kinetic, MD and QM/MM Studies

Biomolecules ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1608
Author(s):  
Irina V. Zueva ◽  
Sofya V. Lushchekina ◽  
Ian R. Pottie ◽  
Sultan Darvesh ◽  
Patrick Masson
Keyword(s):  
Transition State ◽  
Active Site ◽  
Enzyme Inhibitor ◽  
Organophosphorus Compounds ◽  
Palliative Therapy ◽  
Kinetic Studies ◽  
Md Simulations ◽  
Catalytic Active Site ◽  
Slow Binding Inhibitor ◽  
Covalent Intermediate

Kinetic studies and molecular modeling of human acetylcholinesterase (AChE) inhibition by a fluorinated acetophenone derivative, 1-(3-tert-butylphenyl)-2,2,2-trifluoroethanone (TFK), were performed. Fast reversible inhibition of AChE by TFK is of competitive type with Ki = 5.15 nM. However, steady state of inhibition is reached slowly. Kinetic analysis showed that TFK is a slow-binding inhibitor (SBI) of type B with Ki* = 0.53 nM. Reversible binding of TFK provides a long residence time, τ = 20 min, on AChE. After binding, TFK acylates the active serine, forming an hemiketal. Then, disruption of hemiketal (deacylation) is slow. AChE recovers full activity in approximately 40 min. Molecular docking and MD simulations depicted the different steps. It was shown that TFK binds first to the peripheral anionic site. Then, subsequent slow induced-fit step enlarged the gorge, allowing tight adjustment into the catalytic active site. Modeling of interactions between TFK and AChE active site by QM/MM showed that the “isomerization” step of enzyme-inhibitor complex leads to a complex similar to substrate tetrahedral intermediate, a so-called “transition state analog”, followed by a labile covalent intermediate. SBIs of AChE show prolonged pharmacological efficacy. Thus, this fluoroalkylketone intended for neuroimaging, could be of interest in palliative therapy of Alzheimer’s disease and protection of central AChE against organophosphorus compounds.

Transition state stabilization by six arginines clustered in the active site of creatine kinase

2005 ◽  
Vol 1751 (2) ◽  
pp. 178-183 ◽  
Author(s):  
Michael J. Jourden ◽  
Paul R. Geiss ◽  
Michael J. Thomenius ◽  
Lindsay A. Horst ◽  
Melissa M. Barty ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Transition State ◽  
Active Site ◽  
Transition State Stabilization
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