Lecture 11- Enzyme Kinetics 2 Flashcards
What are the 4 basic strategies used by enzymes?
Covalent catalysis,
Acid/Base catalysis, metal ion catalysis, orientation and increasing concentration
Describe covalent catalysis. What is an example?
The active site has a reactive group, like a strong nucleophile, that forms a transient covalent bond during catalysis. Example: lysozyme
Describe acid/base catalysis. What is an example?
A molecule in the active site acts as a proton acceptor or donor.(sometimes both at the same time). And example would be Protease, which cleave peptide bonds, which is also an example of simultaneous acid/base catalysis.
Describe Metal Ion Catalysis.
Metal ions serve as an electrophilic catalyst. In active sites , they increase the acidity of a nearby acid, creating an ionic interaction.
“Metal ion catalyst”
What do you think of?
Nucleophilic Catalysis; increase acidity of nearby acid; cause ionic interaction to facilitate/cause substrate binding.
“Covalent catalysis” what do you think of?
Active site has reactive group, maybe a strong nucleophile, that creates a transient covalent bond during catalysis.
“Acid/base catalysis” what do you think of?
Molecule in active site can act as proton donor or acceptor.
What is important in terms of catalytic activity?
It must be REGULATED.
Describe orientation and increasing concentration.
Enzymes can bind two or more substrate molecules, which increases the local concentration to facilitate/create a reaction, and it can orient the molecules for a reaction.
What is negative feedback?
In metabolic pathways, the product binds to and inhibits the enzyme at the top of the pathway.
“Large quantities of
Product in a metabolic pathway accurate, so the product binds to the enzyme at the top of the pathway to reduce catalytic activity.” What is this an example of?
Negative feedback
How can enzymes increase the speed and efficiency of reactions?
They can form multi-enzyme complexes.
