28 Questions
What is the steady state assumption in enzyme kinetics?
The rate of ES formation equals the rate of ES dissociation
What is the expression for the rate of the reaction in Michaelis-Menten kinetics?
ν = k2 [Eo][S] / [S]+ KM
What is the significance of Km in Michaelis-Menten kinetics?
It is the enzyme-substrate dissociation constant
What is the relationship between Vmax and Km?
Vmax is independent of Km
What is the expression for Vmax in Michaelis-Menten kinetics?
Vmax = k2 [Eo]
What is the term for the substrate concentration at which the rate of the reaction is half of Vmax?
KM
What is the effect of a non-competitive inhibitor on the kinetics of an enzyme?
Decreases Vmax and Km remains the same
What happens to the inhibition by an uncompetitive inhibitor when the substrate concentration is increased?
Inhibition is enhanced
What is the characteristic of a competitive inhibitor?
Binds to the active site and increases Km
What is the effect of a non-competitive inhibitor on the double reciprocal plot?
Two parallel lines intersecting at the Y-axis
What type of inhibitor binds to the free enzyme and the enzyme-substrate complex?
Non-competitive inhibitor
What is the purpose of the Eadie-Hofstee plot?
To determine Km and Vmax
What types of attractions are involved in the binding of substrates to enzymes?
Electrostatic interactions, hydrogen bonds, Van der Waals forces, and hydrophobic interactions
What is the main factor that determines the specificity of enzyme-substrate binding?
The precisely defined arrangement of atoms at the active site
What is the primary function of the enzyme ribonuclease?
To cleave RNA
What is the name of the endoribonuclease enzyme from SARS-CoV?
Nsp15
How many domains are present in the structure of nsp15?
3
What is the quaternary structure of nsp15?
Hexamer
What is the basis of the specificity of an enzyme?
The precise interaction of substrate with the enzyme
What type of inhibition occurs when DIPF reacts with the R groups of amino acids?
Group-specific inhibition
What is the name of the enzyme that cleaves any peptide bond?
Subtilisin
What is the name of the nerve gas that reacts with Ser in acetylcholinesterase?
DIPF
What is the name of the kinetics that describes the relationship between enzyme-substrate binding and reaction rate?
Michaelis-Menten kinetics
What does the equilibrium constant k in the equation k[A][B] = k-1[C] represent?
The extent of the reaction
Why does the reaction rate not increase linearly with an increase in [S]?
Because the enzyme concentration is limiting
What is the overall mechanism of the enzyme catalysis reaction?
Two consecutive reversible reactions
Why can we ignore the reverse reaction in our analysis?
Because we are only measuring the initial rate
What is the significance of the assumption [S] >> [E]o?
The enzyme will be mostly present as the intermediate ES
This quiz covers the basics of enzyme kinetics, including equilibrium constants and the reaction rates of enzymes with substrates.
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