Tag Archives: kinetics
Kinetic Analysis of a Mixture
The figure below illustrates how we can use a kinetic analysis to determine the concentration of two analytes, A and B, provided that there is a difference in their reaction rates. In this example, B reacts more slowly (kB = … Continue reading
Elucidating Mechanisms for the Inhibition of Enzyme Catalysis
When an inhibitor interacts with an enzyme it decreases the enzyme’s catalytic efficiency. An irreversible inhibitor covalently binds to the enzyme’s active site, producing a permanent loss in catalytic efficiency even if we decrease the inhibitor’s concentration. A reversible inhibitor … Continue reading
Lineweaver-Burk Plots
For an enzyme–substrate reaction following a simple mechanism E + S ↔ E–S ↔ E + P consisting of the initial formation of an enzyme–substrate complex, ES, and its subsequent decomposition to form the product, P, and to release the enzyme to react … Continue reading
Enzyme Kinetics
Enzymes are highly specific catalysts for biochemical reactions, with each enzyme showing a selectivity for a single reactant, or substrate. For example, the enzyme acetylcholinesterase catalyzes the decomposition of the neurotransmitter acetylcholine to choline and acetic acid. Many enzyme–substrate reactions … Continue reading
Instrumentation for Kinetic Methods of Analysis
A significant experimental problem when the reaction’s kinetics are fast is ensuring that we rapidly and reproducibly mix the sample and the reagents. For a fast reaction we need to make measurements in a few seconds, or even a few … Continue reading
Quenching a Kinetic Reaction
Monitoring a kinetic reaction is straight-forward, provided that the reaction does not proceed to a appreciable extent during the time it takes to make an individual measurement. As you might expect, this requirement places a serious limitation on a kinetic … Continue reading
Direct-Computation Rate Method
In a rate method we use the differential form of the rate law to determine the analyte’s concentration. As shown here, the rate of a reaction at time t, (rate)t, is the slope of a line tangent to a curve … Continue reading
Taxonomy of Chemical Kinetic Methods of Analysis
Shown here is one useful scheme for classifying chemical kinetic methods of analysis. Methods are divided into two main categories: direct-computation methods and curve-fitting methods. In a direct-computation method we calculate the analyte’s initial concentration, [A]0, using the appropriate rate … Continue reading