Related Experiment Video
Updated: Jun 18, 2025
13:00
Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions
Published on: April 4, 2014
20.6K
Microcalorimetry as a tool in enzymatic kinetics research
Joanna Śliwiak1, Anna Urbanowicz1
1Pracownia Inżynierii Białek, Instytut Chemii Bioorganicznej Polskiej Akademii Nauk w Poznaniu.
Postepy Biochemii
|July 31, 2024
Summary
Isothermal titration calorimetry offers a sensitive, direct method for enzyme kinetics, overcoming limitations of spectrophotometry. This study explores strategies for kinetic calorimetric experiments, enhancing accuracy and efficiency in biocatalysis research.
Area of Science:
- Biochemistry and enzymology
- Biophysical chemistry
Background:
- Enzymes are crucial biocatalysts in therapeutics and industry, necessitating accurate kinetic parameterization.
- Spectrophotometric methods in enzymology face limitations due to substrate/product spectral properties, often requiring complex workarounds.
- Isothermal titration calorimetry (ITC) is emerging as a powerful tool for enzyme kinetics, offering direct heat measurement.
Purpose of the Study:
- To present and discuss two distinct strategies for performing kinetic experiments using isothermal titration calorimetry.
- To highlight the advantages of ITC in enzyme kinetics, including high sensitivity and low reagent consumption.
Main Methods:
- Kinetic experiments were conducted using isothermal titration calorimetry.
- Two specific experimental strategies for kinetic calorimetric measurements were detailed and applied.
Main Results:
- Isothermal titration calorimetry provides a direct, sensitive measurement of enzyme reaction rates.
- The discussed strategies enable accurate kinetic parameterization, overcoming limitations of traditional methods.
Conclusions:
- Isothermal titration calorimetry is a valuable and increasingly recognized technique for studying enzyme kinetics.
- ITC offers a more universal and potentially more accurate approach to enzyme kinetic analysis compared to spectrophotometry.
Related Concept Videos
01:19Introduction to Enzyme Kinetics
19.8K
Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate concentrations. Additional trials with inhibitors or other molecules that affect the reaction rate may also be performed.
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
19.8K
01:19Enzyme Kinetics
96.3K
Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
96.3K
03:02Constant Pressure Calorimetry
85.0K
Calorimetry is a technique used to measure the amount of heat involved in a chemical or physical process or to measure the heat transferred to or from a substance. The heat is exchanged with a calibrated and insulated device called the calorimeter. Calorimetry experiments are based on the assumption that there is no heat exchange between the insulated calorimeter and the external environment. The well-insulated calorimeters prevent the transfer of heat between the calorimeter and its external...
85.0K
02:41Constant Volume Calorimetry
27.0K
Calorimeters are useful to determine the heat released or absorbed by a chemical reaction. Coffee cup calorimeters are designed to operate at constant (atmospheric) pressure and are convenient to measure heat flow (or enthalpy change) accompanying processes that occur in solution at constant pressure. A different type of calorimeter that operates at constant volume, colloquially known as a bomb calorimeter, is used to measure the energy produced by reactions that yield large amounts of heat and...
27.0K
01:13Introduction to Mechanisms of Enzyme Catalysis
8.0K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
8.0K
01:19Turnover Number and Catalytic Efficiency
10.0K
The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from 1 to 1000 molecules per second. Catalase has the known highest turnover number, capable of converting up to 2.8×106 molecules of hydrogen peroxide into water and oxygen per second. Lysozyme has the lowest known turnover number of half a molecule per second.
Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion....
Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion....
10.0K