Mode of Action
What do enzymes do to chemical reactions?
Lower activation energy
How do we measure reaction progress?
Measure loss of substrate or creation of product
What are factors that affect enzyme action? (There are four)
pH, temperature, enzyme concentration, substrate concentration
What does enzyme affinity mean?
How well the enzyme and substrate fit together
What do inhibitors do to enzyme activity?
Lower or stop it
Which model refers to how enzymes and substrates are specific and rigid -- only fit together one way?
Lock & key model
Where do I find Vmax on a graph?
At the highest rate of reaction (where it plateaus)
How many optimal pH's does a single enzyme have?
One
What value do we use to measure enzyme affinity?
Km (Michaelis-Menten constant)
What are the two types of inhibitors?
Competitive & noncompetitive
Which model refers to how enzymes adjust to better fit the substrate as it enters?
Induced fit model
What does Vmax refer to?
When enzymes are fully saturated with substrate.
Why does increasing the amount of substrate only increase enzyme action to a certain limit?
All enzyme active sites get filled, enzymes can only work so fast
Which has higher affinity, an enzyme with a Km=4 or an enzyme with Km=20?
Km=4
If an enzyme does not bind to the active site, where does it bind?
Allosteric site
What kind of proteins are enzymes made from?
What type of tool can we use to measure change in color of enzyme-catalyzed reactions?
Colorimeter
What happens when an enzyme is above its optimal temperature?
It denatures
List 2 factors that can affect enzyme affinity
pH, temperature, inhibitors
Are enzyme inhibitors bad?
NO - enzyme that breaks down ethylene glycol into oxalic acid (toxic) can be inhibited by ethanol
Where are lysozymes found in your body?
Tears, saliva, & other secretions
Which variables go on each axis of a graph?
Independent variable on x axis
Dependent variable on y axis
What would happen to the amount of products produced if enzyme concentration was a limiting factor? (draw a graph)
The graph should show an increase and then plateau
What value do we use to find Michaelis-Menten constant (Km)?
1/2 Vmax
Where does a competitive inhibitor bind?