"Enzyme kinetics is the study of the rates of enzyme-catalysed chemical reactions."
The study of the rates of enzymatic reactions.
Reaction rates: The study of how fast a chemical reaction occurs in a given period of time.
Enzyme structure and function: The study of the composition and roles of enzymes, as well as their catalytic and regulatory properties.
Michaelis-Menten equation: A mathematical formula that describes how the rate of an enzyme-catalyzed reaction depends on the concentration of substrate.
Enzyme inhibition: The process whereby an enzyme's activity is reduced or stopped by certain molecules or ions.
Mechanisms of enzyme catalysis: The various ways in which enzymes lower activation energy, enhance reaction rates, and stabilize transition states.
Allosteric regulation: The process whereby enzymes are turned "on" or "off" by binding of specific molecules to their regulatory subunits.
Enzyme kinetics assays: The tools used to measure enzyme activity and reaction rates, including spectrophotometry, fluorometry, and chromatography.
Enzyme kinetics graphs: The graphical representations of enzyme kinetics data, such as Michaelis-Menten plots, Lineweaver-Burk plots, and double-reciprocal plots.
Enzyme turnover number: The maximum number of substrate molecules that an enzyme can convert into product per unit time.
Enzyme specificity: The property of enzymes to recognize and act upon only certain substrates, while ignoring others.
Enzyme cofactors and coenzymes: The non-protein substances that are required for catalytic activity of certain enzymes, such as metal ions, vitamins, or nucleotides.
Enzyme regulation in vivo: The mechanisms by which enzymes are regulated in living organisms, including feedback inhibition, induction, and repression.
Michaelis-Menten Kinetics: This type of enzyme kinetics is used to describe the rate of an enzyme-catalyzed reaction as a function of the substrate concentration. It assumes that the enzyme-substrate complex is the most significant intermediate in the reaction.
Hill Kinetics: This type of enzyme kinetics is used to describe the cooperative behavior of enzymes. It is a mathematical model that relates the reaction rate to the concentration of the substrate, the number of substrate-binding sites on the enzyme, and a cooperativity factor.
Ping-Pong Kinetics: This type of enzyme kinetics is also called double-displacement kinetics or two-substrate kinetics. This model describes the reaction rate in terms of the concentrations of both substrate and product.
Allosteric Kinetics: This type of enzyme kinetics describes the regulation of an enzyme by the binding of an effector molecule at a site other than the enzyme's active site. This regulation can be either positive or negative.
Competitive Kinetics: This type of enzyme kinetics describes the effects of an inhibitor that competes with the substrate for binding to the enzyme's active site. The inhibitor reduces the concentration of the enzyme-substrate complex, thereby reducing the reaction rate.
Non-Competitive Kinetics: This type of enzyme kinetics describes the effects of an inhibitor that binds to a site on the enzyme other than the active site. This binding reduces the catalytic activity of the enzyme.
Uncompetitive Kinetics: This type of enzyme kinetics describes the effects of an inhibitor that binds to the enzyme-substrate complex. The inhibitor reduces the reaction rate by stabilizing the complex and preventing the release of the product.
"Studying an enzyme's kinetics in this way can reveal the catalytic mechanism of this enzyme."
"An enzyme (E) is typically a protein molecule that promotes a reaction of another molecule, its substrate (S)."
"This binds to the active site of the enzyme to produce an enzyme-substrate complex ES."
"It is transformed into an enzyme-product complex EP and from there to product P via a transition state ES*."
"No, reactions with three or four substrates or products are less common, but they exist."
"Yes, when enzymes bind multiple substrates, such as dihydrofolate reductase, enzyme kinetics can also show the sequence in which these substrates bind."
"An example of enzymes that bind a single substrate and release multiple products are proteases, which cleave one protein substrate into two polypeptide products."
"There is typically one rate-determining step that determines the overall kinetics."
"The structure can suggest how substrates and products bind during catalysis, what changes occur during the reaction, and even the role of particular amino acid residues in the mechanism."
"Some enzymes change shape significantly during the mechanism."
"It is helpful to determine the enzyme structure with and without bound substrate analogues that do not undergo the enzymatic reaction."
"No, not all biological catalysts are protein enzymes. RNA-based catalysts such as ribozymes and ribosomes are essential to many cellular functions."
"The main difference between ribozymes and enzymes is that RNA catalysts are composed of nucleotides, whereas enzymes are composed of amino acids."
"Ribozymes are essential to many cellular functions, such as RNA splicing and translation."
"Ribozymes perform a more limited set of reactions."
"Although their reaction mechanisms and kinetics can be analysed and classified by the same methods."
"Studying an enzyme's kinetics in this way can reveal how a drug or a modifier (inhibitor or activator) might affect the rate."
"This example assumes the simplest case of a reaction with one substrate and one product."
"Examples of enzymes that catalyse two-substrate two-product reactions include the NAD-dependent dehydrogenases such as alcohol dehydrogenase."