Lab4 - Enzyme Kinetics Flashcards
What are enzymes?
They are proteins in organisms that catalyze almost every chemical reaction in cells
Which enzyme did we partially characterize in this lab?
catalase from mammals
How can we calculate the rate of a chemical reaction catalyzed by an enzyme? ex: A <-> (enzyme) B + C
It can be measured by determining:
- how much of the substrate (A) is used up per unit of time
- the amount of any of the products (B or C) produced per unit time
What is enzyme kinematics?
the study of the activity of an enzyme
Studying the kinematics of an enzyme to characterize it and understand how it works. Its performance is determined under various conditions
What are some variables that can affect the activity of an enzyme and can affect the rate of an enzyme-catalyzed reaction?
- Enzyme concentration
- Substrate concentration
- Temperature
- pH
- Presence of cofactors, activators, and inhibitors
What is typically used to report the reaction rate or enzyme activity in enzyme kinematics?
reaction velocity
The initial reaction rate is reported as the initial velocity (V0) of the rxn
The relationship between the rate of the reaction and substrate concentration is:
hyperbolic
The hyperbolic relationship between the rate of the reaction and substrate concentration indicates that the enzyme follows which model of enzyme kinematics?
the Michaelis-Menten model
V0 = Vmax / (1 + (KM / [S]))
The Michaelis constant KM is:
the substrate concentration at 1/2 Vmax. It is an inverse measure of the enzyme’s affinity for its substrate.
Enzyme saturation is the state at which:
all the active sites of an enzyme will be occupied, and the reaction rate will stay constant regardless of the addition of more substrate
Certain characteristics of the enzyme we study in enzyme kinematics are:
- Intrinsic affinity for a substrate
- Optimum temperature
- Optimum pH
- Speed and Efficiency
Catalase is an enzyme found in almost all organisms that are exposed to oxygen. It helps:
to remove hydrogen peroxide by breaking it down into harmless products.
ex: 2 H2O2 <-> (catalase) 2 H2O + O2
