Enzyme Catalysis

Where does the substrate bind on an enzyme?

Enzyme active site

What is the importance of substrate orientation in enzyme catalysis

Proper orientation of substrate in the active site optimizes interaction of a substrate with the enzyme.

What are the 3 key properties of transition state intermediate

Highest energy, highly unstable, and has highest affinity for enzyme

What is the energy required to overcome the kinetic barrier of a reaction (energy needed for a reaction to start)

Activation Energy

How does enzyme catalysis influence activation energy

Lowers activation energy

What kind of catalysis occurs when a reaction is sped up by addition of a base or acid, not consumed in the reaction. (Abstract or donates protons)

Acid base catalysis

What kind of catalysis occurs when an acyl-enzyme intermediate is formed?

Covalent catalysis

How does chymotrypsin utilize various catalytic strategies to reduce overall activation energy of proteolysis?

Splits the single reaction into many steps, each with lower activation energy ultimately lowering the activation energy of the reaction.

What are the 3 sources of catalytic functional groups

Amino acid side chains, cofactors/coenzymes, metal ions

What are the two functional components of a coenzyme?

catalytic functional group + apoenzyme binding site

What is the coenzyme that facilitates activation-transfer?

Thiamine pyrophosphate

What is the coenzyme that facilitates oxidation reduction?

NAD+

What is the difference between activation transfer and oxidation reduction?

Activation transfer forms a covalent bond with the substrate, no covalent bond is formed in redox

What are the 3 roles of metal ions in enzyme catalysis

stabilize negative charges in active site, facilitate substrate binding, coenzyme binding

What kind of inhibitor covalently binds with the active site of an enzyme causing irreversible inhibition?

Covalent inhibitors

What kind of inhibitor looks like the substrate, gets chemically modified by the enzyme to become “true inhibitor” causing enzyme function to stop (kills enzyme)

suicide inhibitors