scholarly journals Kinetic Analysis of Reversible Inhibition of 16α-Hydroxyandrostenedione Aromatization in Human Placental Microsomes by Suicide Substrates of Androstenedione Aromatization

2003 ◽  
Vol 26 (6) ◽  
pp. 890-892 ◽  
Author(s):  
Mitsuteru Numazawa ◽  
Ayako Mutsumi ◽  
Mii Tachibana ◽  
Akiko Yoshimura
Keyword(s):  
Kinetic Analysis ◽  
Reversible Inhibition ◽  
Suicide Substrates

scholarly journals Lipoprotein (a) promotes plasmin inhibition by α2-antiplasmin

1992 ◽  
Vol 286 (1) ◽  
pp. 79-84 ◽  
Author(s):  
J M Edelberg ◽  
S V Pizzo
Keyword(s):  
Kinetic Analysis ◽  
Binding Constants ◽  
Tissue Type ◽  
Additional Mechanism ◽  
Tissue Type Plasminogen Activator ◽  
Lipoprotein A ◽  
Reversible Inhibition ◽  
Trypsin Inhibition ◽  
Type Plasminogen Activator ◽  
Inhibitor Interaction

Plasmin inhibition by alpha 2-antiplasmin (alpha 2AP) is regulated by the vascular components fibrin(ogen) fragments, plasminogen and lipoprotein (a). Kinetic analysis demonstrates that CNBr-derived fibrinogen fragments completely protect plasmin from alpha 2AP. Plasminogen and 6-aminohexanoic acid decrease the rate of inhibition by 5- and 10-fold respectively. These studies show that CNBr-derived fibrinogen fragments and 6-aminohexanoic acid bind plasmin kringle(s) with binding constants of 2 micrograms/ml and 120 microM respectively, and that plasminogen binds to alpha 2AP with an affinity of 0.5 nM. The unmodulated inhibition is not effected by the presence of lipoprotein (a), but in the presence of protective CNBr-derived fibrinogen fragments the rate of inhibition is increased by the presence of the lipoprotein. The kinetics demonstrate that lipoprotein (a) binds to CNBr-derived fibrinogen fragments with an affinity of 4 nM, displacing plasmin from the protective surface. In addition, tissue-type plasminogen activator and trypsin inhibition by alpha 2AP is not slowed by the presence of CNBr-derived fibrinogen fragments or plasminogen (Pg), respectively. These kinetics suggest that the initial reversible interaction between plasmin and alpha 2AP is mediated by binding of the inhibitor to the kringle 1 domain of plasmin, with a reversible inhibition constant (Ki) of 5.0 x 10(-10) M. Under conditions where this kringle-inhibitor interaction is blocked, the reversible inhibition still occurs between the plasmin and alpha 2AP, but the initial Ki is increased to 5.0 x 10(-9) M. These data suggest that, in the circulation, plasmin inhibition by alpha 2AP may be down-regulated by fibrin, fibrin(ogen) fragments and Pg, but up-regulated by lipoprotein (a) in the presence of fibrin or fibrin(ogen) fragments. The lipoprotein (a)-mediated promotion of plasmin inhibition may provide an additional mechanism by which the lipoprotein impairs fibrinolysis and promotes atherosclerosis.

Rapid and Reversible Inhibition of Brain Aromatase Activity

2001 ◽  
Vol 13 (1) ◽  
pp. 63-73 ◽  
Author(s):  
J. Balthazart ◽  
M. Baillien ◽  
G. F. Ball
Keyword(s):  
Aromatase Activity ◽  
Reversible Inhibition ◽  
Brain Aromatase

Kinetic Aspects of the Interaction of Blood Clotting Enzymes

1965 ◽  
Vol 13 (01) ◽  
pp. 155-175 ◽  
Author(s):  
H. C Hemker ◽  
P.W Hemker ◽  
E. A Loeliger
Keyword(s):  
Kinetic Analysis ◽  
Enzyme Kinetics ◽  
Blood Clotting ◽  
Enzyme System ◽  
Enzyme Kinetic ◽  
Clotting Time ◽  
Standard Methods

SummaryApplication of the methods of enzyme-kinetic analysis to the results of clotting tests is feasible and can yield useful results. However, the standard methods of enzyme kinetics are not applicable without modifications imposed by the peculiarities of the blood-clotting enzyme system. The influence of the following complicating circumstances is calculated :1. Substrate is not present in excess.2. Only relative measures exist for concentrations of substrate or enzymes.3. Enzymes and substrates are often added together.4. Reagents are not pure.5. Clotting-time is our only measure for clotting-velocity.Formulas are deduced, which makes it possible to recognize the effect of these complications.

Kinematic and Kinetic Analysis of One-hand and Foot Wheelchair Driving.

1995 ◽  
Vol 32 (4) ◽  
pp. 225-231 ◽  
Author(s):  
Toru HARIGAI ◽  
Shinya KIMURA ◽  
Shuichi KAKURAI
Keyword(s):  
Kinetic Analysis

A New Adsorption Rate Equation in Batch Systems

2018 ◽  
Author(s):  
yongson hong ◽  
Kye-Ryong Sin ◽  
Jong-Su Pak ◽  
Chol-Min Pak
Keyword(s):  
Experimental Data ◽  
Kinetic Analysis ◽  
Adsorption Kinetics ◽  
Rate Equation ◽  
Kinetic Models ◽  
Adsorption Kinetic ◽  
Adsorption Rate ◽  
Batch Systems ◽  
New View

<p><b>In this paper, the deficiencies and cause of previous adsorption kinetic models were revealed, new adsorption rate equation has been proposed and its validities were verified by kinetic analysis of various experimental data.</b> <b>This work is a new view on the adsorption kinetics rather than a comment on the previous adsorption papers.</b></p>

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