1.6 Enzyme Kinetics

Question 0

How are enzymes classified and organized?

Answer 0

According to the type of reaction they catalyze

Question 1

T or F, Enzymes are biocatalysts that increase the rate of chemical reactions and are consumed during the reaction

Answer 1

False. They are NOT consumed during the reaction

Question 2

What is an enzyme and its cofactor called?

Answer 2

Holoenzyme

Question 3

What is an Apoenzyme

Answer 3

The protein portion of the holoenzyme

Question 4

Prosthetic groups

Answer 4

Tightly bound coenzyme

Question 5

Three types of enzymatic reactions?

Answer 5

1. Random
2. Sequential Displacement
3. Double Displacement (ping-pong)

Question 6

What is Double displacement enzymatic reactions

Answer 6

When one or more products are released before all substrates have been bound by enzyme

Question 7

Rate of reaction in enzyme kinetics is directly proportional to what?

Answer 7

[E] and [S]

Question 8

Allosteric enzymes give what type of curve on the substrate vs V0 graph?

Answer 8

Sigmoidal curve

Question 9

What is the Km

Answer 9

It reflects the affinity of the enzyme for the substrate

Question 10

Km = what?

Answer 10

the [substrate] at 1/2 Vmax

Question 11

T or F, Km varies with Enzyme concentration?

Answer 11

False, It does not vary with enzyme concentration. It is dependent upon the [S]

Question 12

Small Km = what type of affinity that E has for S

Answer 12

A high affinity

Question 13

_______ Km = low affinity of E for S

Answer 13

Large Km

Question 14

What does the slope represent on the Lineweaver-Burke plot

Answer 14

slope = Km/Vmax

Question 15

What is the x axis on the Lineweaver-Burke plot

Answer 15

1/[S]

Question 16

Y-axis of the Lineweaver-Burke plot

Answer 16

1/V0

Question 17

What is the turnover number

Answer 17

number of molecules of [S] converted to product per enzyme per second

Question 18

High Kcat and low Km are markers of what?

Answer 18

Enzyme efficiency

Question 19

Explain reversible enzyme inhibition

Answer 19

Enzyme inhibition in which there are noncovalent bonds used and the enzyme can continue functioning

Question 20

What is irreversible enzyme inhibition

Answer 20

Enzyme does not regain activity

Question 21

What are the two most common reversible enzyme inhibitions

Answer 21

1. Competitive

2. Non-competitive

Question 22

Which type of inhibitor reduces rate of catalysis by reducing the proportion of enzyme molecules bound to a substrate?

Answer 22

Competitive inhibitor

Question 23

What type of inhibitor functions by binding to the enzyme at a different location than the active site?

Answer 23

Non-competitive inhibitor

Question 24

What type of enzyme inhibitor increases the Km

Answer 24

Competitive Inhibitor

Question 25

What happens to a competitive inhibitor if extra substrate is added

Answer 25

The inhibition can be dampened

Question 26

Which inhibitor decreases the Vmax and keeps Km the same

Answer 26

Noncompetitive Inhibitor

Question 27

Why does a noncompetitive inhibitor not affect the Km

Answer 27

The inhibitor does not interfere with the substrate and enzyme binding.

Question 28

What is an Isozyme?

Answer 28

Alternative form of same enzyme activity that exist in different proportions in different tissues

Question 29

What is a Proenzyme or a Zymogen

Answer 29

Inactive storage forms of enzymes