Regulatory Strategies of Enzymes

Question 1

Binding energy

Answer 1

Free energy released in the formation of a large number of weak interactions between enzyme and substrate that is in transition state

Question 2

Covalent catalysis

Answer 2

Making covalent bonds to substrate

Increases binding energy

Question 3

General acid-base chemistry

Answer 3

Movement of electrons at active site of enzyme

Increases binding energy

Question 4

Catalysis by approximation

Answer 4

Bring active site and substrate together

Increases binding energy

Question 5

Metal ion catalysis

Answer 5

Using a cofactor to increase the binding energy

Question 6

Goal of proteolysis

Answer 6

Enabling attack of a molecule that doesn’t want to be attacked (amino acid chain can be stabilized through resonance, making it less susceptible to nucleophilic attack)

Question 7

Serine as a nucleophile

Answer 7

Serine splits a protein chain into 2 pieces by latching onto the carbonyl group
Water can then attach to the carbonyl, breaking off the serine

Question 8

Catalytic triad

Answer 8

Part of serine protease
Stronger nucleophile than -OH
3 polar amino acids attached to an enzyme base

Question 9

How serine protease performs proteolysis

Answer 9

Catalytic triad reacts with the carbonyl group of the protein to create a reactive nucleophile and the enzyme portion stabilizes the transition state

Question 10

Which of the 3 amino acids in the catalytic triad are essential for its function

Answer 10

All 3 amino acids are critical to the function of the catalytic triad

Question 11

Reason why reaction of serine protease with nonfunctional catalytic triad is faster than the uncatalyzed reaction

Answer 11

Even without the catalytic triad, the enzyme backbone can still bind to substrate

Question 12

Common reaction of proteases

Answer 12

Nucleophilic attack of carbonyl carbon of target protein

Question 13

Allosteric regulation

Answer 13

Regulate enzyme from spot other than active site

Question 14

Isozymes

Answer 14

Multiple forms of an enzyme (different amino acids, same reaction)
Similar active sites, different allosteric sites

Question 15

Isozymes and enzyme regulation

Answer 15

Having more than 1 type of enzyme for a specific function can enable enzymes to work in different parts of the body
Temporal and spatial separation of enzymes

Question 16

ATP as an allosteric modifier of metabolic enzymes

Answer 16

Energy sensor: adding ATP to an enzyme can tell the enzyme if there is enough energy for it to be able to work

Question 17

End products of catabolic pathways and allosteric regulation

Answer 17

Final products of catabolic processes allosterically regulate the original enzyme
Products of catabolic processes commonly inhibit at points of energy investment

Question 18

Heterotrophic effect

Answer 18

Different molecule from substrate influences rate of reaction

Question 19

Homotrophic effect

Answer 19

Substrate influences rate of reaction

Question 20

Pros of phosphorylation

Answer 20

2 negative charges disrupt/create electrostatic interactions
3 potential hydrogen bonds
Shifts balance of free energy
Amplification of signal
Can be reversible through actions of phosphatase

Question 21

Domains of kinases

Answer 21

Domain specific for binding to substrate

Domain specific for regulation by ATP binding

Question 22

Zymogen

Answer 22

Molecule that is cleaved to make a functional enzyme

Precursor to enzyme

Question 23

Zymogen cascade

Answer 23

Amplification: 1 zymogen turns on the next which turns on the next…

Question 24

Results of proteolysis

Answer 24

Cutting a protein changes its structure and makes new ionic charges