Lecture 4 - Enzymology Flashcards
What is an enzyme?
a generic term for a biological catalyst
What type of molecules are enzymes normally?
proteins
How do the primary amino acid affect the tertiary structure?
It gives it function.
What is the common suffixes for enzymes?
-ase
What are oxidoreductases?
catalyze transfer of electrons from reductant (electron donor) to the oxidant (electron acceptor)
What are transferases?
an enzyme that transfers functional groups between donor and acceptor molecules
What do hydrolases do?
add water across a bond
What do lyases do?
add water, ammonia, or carbon dioxide to produce double bonds
What do isomerases do?
carry out many kinds of isomerization
What do ligase do?
catalyze reactions in which two chemical groups are joined using ATP
How do apoenzymes relate to holoenzyme?
cofactors join the apoenzyme (inactive protein portion) in order to create the holoenzyme (active enzyme)
Which things do enzymes prefer?
certain temperatures and pH
What is substrate specificity?
unique fit of substrate with enzyme which controls selectivity
What is different about the induced-fit model?
enzyme changes conformation to fit the substrate
How are enzymes used in regulation?
phosphorylation acts as an on/off switch based on availability
Do enzymes appear as a reaction product?
No
Do enzymes affect the equilibrium?
No
Do enzymes need large amounts of quantities in order to work?
No
How do enzymes work?
They lower the activation energy of the reaction.
If the rate constant changes, does the equilibrium constant change?
No
What does Vmax stand for?
maximum velocity of the enzyme reaction
What is Km?
The substrate concentration at 1/2 of the maximum velocity of the enzymatic reaction
When k2 is greather than k3, what is Km an estimate of?
the dissociation constant (Kd)
What does a small Km mean?
tight binding, meaning there is a greater chance of an enzyme-substrate complex
