C1.1: Enzymes Flashcards
What type of proteins are enzymes?
Globular
What do enzymes do?
Act as catalyst — speeds up the process but doesn’t alter the process
Most proteins are..
enzymes
What’s the suffix of enzyme name? Generally.
-Ase
e.g.:
Enzyme of sucrose is sucrase (sucrose -> fructose and glucose — breaks down because it’s a polysaccharide)
How do enzymes work?
They weaken bonds which lowers activation energy
- E.g.: in catabolic reactions, if the bonds present are weakened, it would require less activation energy to start the reaction
Define activation energy
The energy to start a chemical reaction
What is an active site?
Where the substrate binds to enzyme
What does the Induced Fit Model say?
The enzyme will adjust the shape of the active site to fit with the enzyme
But, *the enzyme will return to orig shape
like a desperate boyfie jk
-induced by the substrate
What is the area that’s not the active site?
Allosteric site
How can the temperature affect enzymes? [4]
Generally: Thermal energy -> mvmt (KE) -> more collisions between substrate and enzyme;
- High temp: v enzyme stability = v hydrogen bonds of enzyme = enzyme loses shape;
- Low temp = v thermal energy = v enzymatic activity
- Optimal temp: *rate of enzyme @ peak
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Describe the two types of enzyme inhibitors
a.) Competitive inhibitors - chemicals resembling enzyme’s normal substrate and competes w/ actual for active site
- the substrate will just be misplaced but will be at active site after comp inhib
- just slow down the process but the process will still happen
b.) Non-competitive inhibitors - does not denature the enzyme but changes the shape of active site to avoid substrate to enzyme.
- makes the enzyme non-functional — denaturation
Differentiate the induced fit model vs the key and hole model
Induced fit model can hold more substrate because enzyme changes shape.
Key hole model says that the substrate and the enzyme have complimentary shapes in the beginning -> more rigid
What are the two main types of metabolism?
1.) Anabolism
- simple -> complex (e.g. polymerization — condensation)
2.) Catabolism
- complex -> simple (ie. breaking down — hydrolysis)
Can enzymes only do catabolic reactions?
NO! They can do anabolic ones too!
What do we call it when a substrate is bound to the enzyme?
Enzyme-substrate complex
What happens when substrate concentration > enzyme’s capacity?
There’s a plateau (constant enzyme activity) because the enzymes are occupied.
- The substrates can be accompanied, it’s just there’s a waiting line
How to draw the optimum area in curved graphs?
The optimum area is the highest point and should be aligned with number.
-> for enzyme activity = start of curve
Evaluate this graph
0% Inhibitors - normal
25% Inhibitors - slower, but the enzymes are still working
50% Inhibitors - substrates have competition so lower enzyme activity compared to the others, the enzymes not occupied
- no plateau due to 50% chance of actual substrates binding
Describe this graph of non-competitive inhibition
^ Increase in substrate concentration = v no. of enzymes able to accommodate them
- e.g. 25% inhibitor = 25% of enzymes not working — so still plateau, but later plateau than 50%
How can lactose-intolerant people drink milk and other dairy products?
They will use
How does pH affect enzymatic activity?
Change in pH = change in enzyme/denaturation = protein solubility + change in shape of molecule
- “^ change in shape = v binding w/ substrate”
- Different optimum pH for different enzymes (like temp)
