Block 2 - Enzyme Allosterics Flashcards Preview

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Flashcards in Block 2 - Enzyme Allosterics Deck (13):
1

What are allosteric enzymes? What happens after one substrate binds to the enzyme?

Allosteric enzymes display coopertivity with their substrate and have more than one active site. Bind of one substrate facilitates binding of subsequent substrates.

2

What is the Hill equation? What does n measure?

The Hill equation measures the kinetics of allosteric enzymes. N is the degree of cooperativity. The equation is similar to Michaelis-Menten, with [S]^n

3

If enzymes are allosteric, do they have a broad or narrow range of activity response towards [S]? What do they act like?

Narrow range of activity, acting like a switch

4

What is tense and relaxed states with respect to allosteric enzymes?

Tense is when the enzyme is stressed, relaxed is when the enzyme is more pleased with its current conformation.

5

At low [S], is an allosteric enzyme tense or relaxed?

Tense

6

At high [S], is an allosteric enzyme tense or relaxed?

Relaxed

7

Will inhibitors of an allosteric enzyme stabilize the relaxed or tense state of the enzyme?

Tense

8

Will activators of an allosteric enzyme stabilize the relaxed or tense state of the enzyme?

Relaxed

9

Compare and contrast homotrophic and heterotrophic regulation

Homotrophic regulation is when binding of one molecule changes the affinity for other identical molecules to bind. Almost always positive (allosteric enzymes an example.) Heterotrophic regulation uses a molecule distinct from the substrate to bind at a site other than the catalystic site, which modulates activity of an enzyme.

10

What do positive v-system effectors (activators) change? How?

Vmax, increase

11

What do negative v-system effectors (inhibitors) change? How?

Vmax, decrease

12

What do positive K-system effectors change? How?

K(0.5), decrease

13

What do negative K-system effectors change? How?

K(0.5), increase