1.6 Enzyme Kinetics Flashcards Preview

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Flashcards in 1.6 Enzyme Kinetics Deck (30):
0

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

False. They are NOT consumed during the reaction

1

How are enzymes classified and organized?

According to the type of reaction they catalyze

2

What is an enzyme and its cofactor called?

Holoenzyme

3

What is an Apoenzyme

The protein portion of the holoenzyme

4

Prosthetic groups

Tightly bound coenzyme

5

Three types of enzymatic reactions?

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

6

What is Double displacement enzymatic reactions

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

7

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

[E] and [S]

8

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

Sigmoidal curve

9

What is the Km

It reflects the affinity of the enzyme for the substrate

10

Km = what?

the [substrate] at 1/2 Vmax

11

T or F, Km varies with Enzyme concentration?

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

12

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

A high affinity

13

_______ Km = low affinity of E for S

Large Km

14

What does the slope represent on the Lineweaver-Burke plot

slope = Km/Vmax

15

What is the x axis on the Lineweaver-Burke plot

1/[S]

16

Y-axis of the Lineweaver-Burke plot

1/V0

17

What is the turnover number

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

18

High Kcat and low Km are markers of what?

Enzyme efficiency

19

Explain reversible enzyme inhibition

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

20

What is irreversible enzyme inhibition

Enzyme does not regain activity

21

What are the two most common reversible enzyme inhibitions

1. Competitive
2. Non-competitive

22

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

Competitive inhibitor

23

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

Non-competitive inhibitor

24

What type of enzyme inhibitor increases the Km

Competitive Inhibitor

25

What happens to a competitive inhibitor if extra substrate is added

The inhibition can be dampened

26

Which inhibitor decreases the Vmax and keeps Km the same

Noncompetitive Inhibitor

27

Why does a noncompetitive inhibitor not affect the Km

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

28

What is an Isozyme?

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

29

What is a Proenzyme or a Zymogen

Inactive storage forms of enzymes