Determining proton positions in an enzyme-inhibitor complex is a first step for theoretical mechanistic studies of aspartic proteinases

1993 ◽  
Vol 85 (1-3) ◽  
pp. 231-247 ◽  
Author(s):  
Amiram Goldblum ◽  
Meir Glick ◽  
Anwar Rayan
Keyword(s):  
Enzyme Inhibitor ◽  
Mechanistic Studies ◽  
Aspartic Proteinases ◽  
Inhibitor Complex

scholarly journals Mechanistic Studies of the Inactivation of TEM-1 and P99 by NXL104, a Novel Non-β-Lactam β-Lactamase Inhibitor

2010 ◽  
Vol 54 (12) ◽  
pp. 5132-5138 ◽  
Author(s):  
Thérèse Stachyra ◽  
Marie-Claude Péchereau ◽  
Jean-Michel Bruneau ◽  
Monique Claudon ◽  
Jean-Marie Frère ◽  
...  
Keyword(s):  
Potent Inhibitor ◽  
Enzyme Inhibitor ◽  
Dissociation Constants ◽  
Mechanistic Studies ◽  
Ionization Time ◽  
Inhibitor Complex ◽  
Class A ◽  
Flight Mass Spectrometry ◽  
Covalent Adduct ◽  
Improved Stability

ABSTRACT NXL104 is a potent inhibitor of class A and C serine β-lactamases, including KPC carbapenemases. Native and NXL104-inhibited TEM-1 and P99 β-lactamases analyzed by liquid chromatography-electrospray ionization-time of flight mass spectrometry revealed that the inactivated enzymes formed a covalent adduct with NXL104. The principal inhibitory characteristics of NXL104 against TEM-1 and P99 β-lactamases were determined, including partition ratios, dissociation constants (K), rate constants for deactivation (k 2), and reactivation rates. NXL104 is a potent inhibitor of TEM-1 and P99, characterized by high carbamylation efficiencies (k 2/K of 3.7 × 105 M−1 s−1 for TEM-1 and 1 × 104 M−1 s−1 for P99) and slow decarbamylation. Complete loss of β-lactamase activity was obtained at a 1/1 enzyme/NXL104 ratio, with a k 3 value (rate constant for formation of product and free enzyme) close to zero for TEM-1 and P99. Fifty percent inhibitory concentrations (IC50s) were evaluated on selected β-lactamases, and NXL104 was shown to be a very potent inhibitor of class A and C β-lactamases. IC50s obtained with NXL104 (from 3 nM to 170 nM) were globally comparable on the β-lactamases CTX-M-15 and SHV-4 with those obtained with the comparators (clavulanate, tazobactam, and sulbactam) but were far lower on TEM-1, KPC-2, P99, and AmpC than those of the comparators. In-depth studies on TEM-1 and P99 demonstrated that NXL104 had a comparable or better affinity and inactivation rate than clavulanate and tazobactam and in all cases an improved stability of the covalent enzyme/inhibitor complex.

m-[o-(2-Chloro-5-Fluorosulfonylphenylureido)Phenoxybutoxy]Benzamidine: Affinity Labeling Reagent Which Can Identify Secondary Binding Sites of Coagulation Complement and Fibrinolytic Serine Proteases

1979 ◽  
Author(s):  
D Bing ◽  
D Robison ◽  
J Andrews ◽  
R Laura
Keyword(s):  
Binding Sites ◽  
Serine Proteases ◽  
Enzyme Inhibitor ◽  
Molecular Model ◽  
Factor Xa ◽  
Affinity Labeling ◽  
Catalytic Center ◽  
Inhibitor Complex ◽  
Polypeptide Chains ◽  
Kinetics Of

We have determined that m-[o-(2-chloro-5-fluorosulfonylphenylureido)phenoxybutoxy]benza-midine [mCP(PBA)-F] is an affinity labeling reagent which labels both polypeptide chains of thrombin, factor Xa, complement component CIS and plasmin. As this means it is reacting outside of the catalytic center, we have called this reagent an exo-site affinity labeling reagent. Progressive irreversible inhibition of these enzymes by this reagent is rapid (k1st 2.5-4.6 x 10-3sec-1), the kinetics of inactivation are consistent with inhibition proceding via formation of a specific enzyme-inhibitor complex analogous to a Michaelis-Menton complex (KL - 115-26 μM), and diisopropylfluorophosphate or p-amidino-phenylmethanesulfonyfluoride Prevent labeling by [3H]mCP(PBA)-F. A molecular model of mCP(PBA)-F shows that the reactive SO2F group can be 17 A from the cationic amidine. The data are consistent with the hypothesis that both peptide chains are required for the specific proteolytic activity exhibited by these proteases and that the peptide chain which does not contain the active site serine is close to the catalytic center. (Supported by NIH and AHA grants

Optimal Duration of the Preincubation Phase in Enzyme Inhibition Experiments

2020 ◽  
Author(s):  
Petr Kuzmic
Keyword(s):  
Enzyme Inhibition ◽  
Dose Response ◽  
Enzyme Inhibitor ◽  
Single Point ◽  
Association Rate ◽  
Weakly Bound ◽  
Inhibitor Complex ◽  
Dissociation Equilibrium ◽  
Optimal Duration ◽  
Algebraic Formula

This report describes an algebraic formula to calculate the optimal duration of the pre-incubation phase in enzyme-inhibition experiments, based on the assumed range of expected values for the dissociation equilibrium constant of the enzyme–inhibitor complex and for the bimolecular association rate constant. Three typical experimental scenarios are treated, namely, (1) single-point primary screening at relatively high inhibitor concentrations; (2) dose-response secondary screening of relatively weakly bound inhibitors; (3) dose-response screening of tightly-bound inhibitors.

A Very Short Hydrogen Bond Provides Only Moderate Stabilization of an Enzyme-Inhibitor Complex of Citrate Synthase

Biochemistry ◽  
1994 ◽  
Vol 33 (25) ◽  
pp. 7753-7759 ◽  
Author(s):  
Ken C. Usher ◽  
S. James Remington ◽  
David P. Martin ◽  
Dale G. Drueckhammer
Keyword(s):  
Hydrogen Bond ◽  
Citrate Synthase ◽  
Enzyme Inhibitor ◽  
Inhibitor Complex ◽  
Short Hydrogen Bond

scholarly journals Kinetic properties of the primary inhibitor of plasmin from human plasma

1977 ◽  
Vol 163 (2) ◽  
pp. 389-391 ◽  
Author(s):  
U Christensen ◽  
I Clemmensen
Keyword(s):  
Human Plasma ◽  
Enzyme Inhibitor ◽  
Kinetic Properties ◽  
Inhibitor Complex ◽  
Rapid Formation ◽  
Plasmin Inhibitor

The interaction of human plasmin with the newly discovered alpha2-plasmin inhibitor was investigated. It was found from rate measurements that the reaction involves the rapid formation of a first enzyme-inhibitor complex, followed by the slow irreversible transition to another complex. L-Lysine influences the first step, but not the second.

Enzyme-Inhibitor Complex in a Tryptophan-Requiring Mutant of Neurospora crassa

Science ◽  
1957 ◽  
Vol 126 (3282) ◽  
pp. 1068-1069 ◽  
Author(s):  
S. R. SUSKIND ◽  
L. I. KUREK
Keyword(s):  
Neurospora Crassa ◽  
Enzyme Inhibitor ◽  
Inhibitor Complex

scholarly journals Structure of Enzyme-Inhibitor Complex Determined by Neutron Crystallography

2013 ◽  
Vol 55 (1) ◽  
pp. 47-51
Author(s):  
Taro TAMADA ◽  
Motoyasu ADACHI ◽  
Kazuo KURIHARA ◽  
Ryota KUROKI
Keyword(s):  
Enzyme Inhibitor ◽  
Inhibitor Complex ◽  
Neutron Crystallography

TWO-SIDE IMMUNOASSAYS OF ENZYME-INHIBITOR COMPLEXES FOR THE DIAGNOSIS OF THROMBOPHILIC STATES

1987 ◽  
Author(s):  
H Bleyl
Keyword(s):  
Heart Surgery ◽  
Enzyme Inhibitor ◽  
Open Heart Surgery ◽  
Coagulation Cascade ◽  
Clotting Factors ◽  
Inhibitor Complex ◽  
At Iii ◽  
Complex Measurement ◽  
Sandwich Assays ◽  
Time Of Admission

The diagnosis of prethrombotic states requires methods which detect products of intravasal activation of the coagulation cascade.Two-side immunoassays for antithrombin complexes with clotting factors were developed (IXi-AT, Xi-AT, IIi- AT). These sandwich assays permit the diagnosis of hypercoagulability in the presence or absence of heparin. The biological half live time of the thrombin-antithrombin-complex was found to be about 15 min. Healthy young men 20-25 years old (n=30) have a thrombin-antithrombin-complex concentration of 0.4 ± 0.2 mU/ml thrombin equivalent (S 2238). Patients with acute myocardial infarction (n=40) showed at the time of admission to the hospital up to 10-fold (n=14), up to 100-fold (n=13) more than 100-fold (n=13) elevated thrombin-antithrombin-complex concentrations. Patients with gastrointestinal cancer showed sometime excessive elevated enzyme-inhibitor complexes.No correlation was found between thromboplastine time (Quick) and complex concentration in patients under anticoagulant therapy with dicumarole. In patients under dialysis as well as in patients under open heart surgery with extracorporal circulation, the biocompatibility can be monitored by inhibitor complex measurement.

Synthesis and SAR of Thrombin Inhibitors Incorporating a Novel 4-Amino-Morpholinone Scaffold:  Analysis of X-ray Crystal Structure of Enzyme Inhibitor Complex

2003 ◽  
Vol 46 (19) ◽  
pp. 3985-4001 ◽  
Author(s):  
Jonas W. Nilsson ◽  
Ingemar Kvarnström ◽  
Djordje Musil ◽  
Ingemar Nilsson ◽  
Bertil Samulesson
Keyword(s):  
Crystal Structure ◽  
Enzyme Inhibitor ◽  
Thrombin Inhibitors ◽  
X Ray ◽  
Inhibitor Complex
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