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.

scholarly journals On the Reaction of Human Plasmin with the Primary Inhibitor of Plasmin from Human Plasma

1977 ◽  
Author(s):  
Ulla Christensen
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Dissociation Constant ◽  
Human Plasma ◽  
Ethyl Ester ◽  
Enzyme Inhibitor ◽  
Specific Time ◽  
Inhibitor Complex ◽  
Reversible Formation ◽  
Rate Of Consumption

The interaction of human plasmin with the recently discovered primary inhibitor of plasmin from human plasma has been investigated. The inhibitor is an α2-glycoprotein with a molecular weight of 60000. Pure preparations of plasmin and the inhibitor were incubated for a specific time, after which residual plasmin was determined from measurements of the rate of consumption of α-N-bensoyl-L-arginine ethyl ester. Experiments were made over ranges of both plasmin and inhibitor concentrations and for a variety of incubation times. The results show that the reaction consists of at least two steps: rapid, reversible formation of an enzyme-inhibitor complex with the dissociation constant, K = 3nM, followed by a slow, irreversible transition with a rate constant, k = 6.5 10-3s-1. Amino acids with anti-fibrinolytic effect inhibit the formation of the first complex, but not its further transition.

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 Different N-terminal forms of α2-plasmin inhibitor in human plasma

1993 ◽  
Vol 291 (2) ◽  
pp. 623-625 ◽  
Author(s):  
K Bangert ◽  
A H Johnsen ◽  
U Christensen ◽  
S Thorsen
Keyword(s):  
Human Plasma ◽  
Cdna Sequence ◽  
Recognition Site ◽  
Signal Peptidase ◽  
Stable Complex ◽  
N Terminus ◽  
Functional Implications ◽  
Plasmin Inhibitor

Mature alpha 2-plasmin inhibitor in human plasma has 12 more N-terminal residues than hitherto anticipated. The first residue is the methionine at position 28, downstream from the N-terminus of the pre-protein. The cDNA sequence predicts that the site cleaved upon formation of the mature inhibitor is a typical signal-peptidase recognition site. The mature inhibitor (464 residues) and the previously reported, and presumably degraded, form with N-terminal asparagine (452 residues), are present in plasma in about equal amounts. They both form a stable complex with plasmin. Recent studies on a recombinant alpha 2-plasmin inhibitor suggest that the 12 additional residues have functional implications [Sumi, Ichikawa, Nakamura, Miura and Aoki (1989) J. Biochem. 106, 703-707].

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.

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