PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Physical Chemistry → Chemical kinetics ↓


Catalysis and enzyme kinetics


Introduction to catalysis

Catalysis is a process in which the rate of a chemical reaction is increased by the presence of a substance called a catalyst. The catalyst is not consumed by the reaction, which means it can be used again and again. Catalysts work by providing an alternative reaction pathway with a lower activation energy, which provides enough energy for more reactant particles to react.

Types of catalysis

There are two main types of catalysis: homogeneous and heterogeneous. In homogeneous catalysis, the catalyst and reactants are in the same phase, usually a liquid or gas. An example of homogeneous catalysis is the acid-catalyzed esterification of an alcohol and an acid. In heterogeneous catalysis, the catalyst is in a different phase than the reactants. This is often seen in industrial applications such as the Haber process for the synthesis of ammonia, where solid iron catalyzes reactions between gaseous nitrogen and hydrogen.

Role of catalysts

Catalysts are important in many industrial and biological processes. In industrial chemistry, catalysts help make chemicals faster and more efficiently, which is important for economical and sustainable production. For example, in the manufacture of sulfuric acid, the contact process uses vanadium(V) oxide as a catalyst to increase the reaction rate.

In biological systems, enzymes act as nature's catalysts. Enzymes are proteins that catalyze biochemical reactions, enabling life-sustaining processes to occur at rates that sustain life. Without enzymes, most biochemical reactions occur at rates too slow to sustain life.

Enzyme kinetics

Enzyme kinetics is the study of how biochemical processes occur with the help of enzymes. It involves understanding the rates of enzymatic reactions and how various factors affect these rates. The study of enzyme kinetics is important for understanding metabolic pathways, designing drugs, and developing new therapies.

Michaelis-Menten kinetics

A fundamental concept in enzyme kinetics is the Michaelis-Menten model. This model describes how the rate of enzymatic reactions depends on the concentration of the substrate. The equation for this model is:

    v = (Vmax [S]) / (Km + [S])

Where:

  • v is the reaction rate.
  • [S] is the substrate concentration.
  • Vmax is the maximum reaction rate.
  • Km is the Michaelis constant, which is the substrate concentration at which the reaction rate is half of Vmax.

Visual example: reaction path with and without catalyst

Below is a visual representation of how catalysts affect the reaction pathway. Note how the presence of the catalyst lowers the activation energy:

Reactants Products stimulated not induced

Factors affecting enzyme activity

Many factors affect enzyme activity, thereby affecting the rate of enzymatic reactions. These include:

  • Temperature: Enzymes have an optimal temperature range. High temperatures can denature enzymes, while low temperatures slow down the reaction rate.
  • pH level: Enzymes also have an optimal pH range. Deviation from this range can lead to a decrease in enzyme activity.
  • Substrate concentration: Increasing the substrate concentration increases the reaction rate, but only up to the point where the enzymes become saturated.
  • Enzyme concentration: Increasing the enzyme concentration usually increases the reaction rate, provided there is an excess of substrate.

Enzyme inhibition

Enzyme inhibitors are molecules that reduce the activity of enzymes. There are two main types of inhibitors: competitive and non-competitive. Competitive inhibitors compete with the substrate for the active site, while non-competitive inhibitors bind to an alternative site and change the shape of the enzyme, making it less effective.

Lesson example: blocking mechanism

Consider two scenarios:

  1. The competitive inhibitor binds to the active site, preventing substrate molecules from binding to the enzyme. Enzyme activity can be restored by increasing substrate concentrations.
  2. A non-competitive inhibitor binds to a site other than the active site, thereby changing the shape of the enzyme. Changes in substrate concentrations do not restore enzyme activity.

Applications in drug development

Understanding enzyme kinetics is important for the design of effective drugs. Inhibitors are often used as drugs to reduce the activity of target enzymes related to diseases. For example, ACE inhibitors are used to treat hypertension by inhibiting the angiotensin-converting enzyme.

Conclusion

Catalysis and enzyme kinetics are fundamental concepts in physical chemistry that have profound implications for both industrial processes and biological systems. By understanding how catalysts and enzymes work, scientists and engineers can design more efficient systems, develop new medicines, and gain deeper insights into the mechanisms of life.


PHD → 3.3.3


U
username
0%
completed in PHD

← Prev (3.3.2)
Mechanism and rate laws
Next (3.3.4) →
Reaction dynamics

Comments 



Catalysis and enzyme kinetics

https://www.chemistryelite.com/phd/3.3.3?ceal=en