Enzymes

Question 1

Conjugated proteins
Catalyst/Speed up or hasten biochemical reaction
Very efficient and effective
Highly specific

Answer 1

Enzymes

Question 2

Enzymes accelerate chemical reactions by decreasing

Answer 2

the energy of activation of the reaction

Question 3

Protein portion of enzyme

Answer 3

Apoenzyme

Question 4

Non protein portion of enzyme

Answer 4

inorganic e.g. metal ions -> co factors

organic e.g. NAD, FAD, FMN -> coenzyme

Question 5

Inorganic non protein portion of enzyme

Answer 5

Cofactors

Question 6

Organic non-protein portions

Usually vitamins

Answer 6

Coenzyme

Question 7

Apoenzyme (protein) + Cofactor/Coenzyme (nonprotein)

Answer 7

Holoenzyme

Question 8

Amount of energy required to produce a transition state and bring about a reaction

Answer 8

Energy of activation (Ea)

Question 9

Enzymes that catalyze oxidations and reductions

Answer 9

Oxidoreductases

Question 10

Enzymes that catalyze transfer of moieties such as glycosyl, methyl, or phosphoryl groups

Answer 10

Transferases

Question 11

Enzymes that catalyze hydrolytic cleavage of C-C, C-O, and other covalent bonds

Answer 11

Hydrolases

Question 12

Enzymes that catalyze CLEAVAGE of C-C, C-O and other COVALENT bonds by

Atom elimination
Generation of double bonds

Answer 12

Lyases

Question 13

Enzymes that catalyze GEOMETRIC or STRUCTURAL changes within a molecule

Answer 13

Isomerases

Question 14

What is the action of glutaminase enzyme?

Answer 14

Hydrolytic cleavage
Hydrolase

Catalyzes glutamine to glutamate

Question 15

Two sites of enzymes

Answer 15

Active site

Substrate recognition site

Question 16

The substrate can bind to the enzyme to form an

Answer 16

Enzyme-Substrate Complex

Question 17

Substrate binds to the enzyme at the

Answer 17

active site

Question 18

When the reaction is complete the products are released and the enzyme can be used again

The result:

Answer 18

reaction product

Question 19

Substrate + Active Site = ES Complex

Substrate perfectly fits on active site

Answer 19

Rigid Template Model
(Emil Fischer)
Lock and Key Model

Question 20

As substrate binds, enzyme undergoes a confirmational change that repositions amino acids in the active site and increases interactions with the substrate

Answer 20

Induced Fit Model
(Daniel Koshland)
Flexible Fit Model

Question 21

Active site assumes shapes that are complementary to that of the substrate only after the substrate is bound

Answer 21

Induced Fit Model
(Daniel Koshland)
Flexible Model

Question 22

Is the velocity approached at a saturating concentration of the substrate

Answer 22

Vmax

Question 23

Is the concentration of the substrate required to produce 1/2 Vmax

Answer 23

Km

Question 24

Km =

Answer 24

Km = 1/2 Vmax

Question 25

Relates the initial velocity to substrate concentration [S] and maximum velocity

Answer 25

Michaelis Menten Equation

Question 26

Initial velocity is directly proportional to

Answer 26

Vmax

Question 27

Initial velocity is inversely proportional to

Answer 27

Km

Question 28

This equation describes how reaction velocity varies with substrate equation sigmoidal

Answer 28

Michaelis-Menten Equation

Question 29

vi =

Answer 29

vi initial velocity= Vmax / Km

Question 30

is the S at half maximum velocity is a measure of the affinity of an enzyme for its substrate

Answer 30

Km

Question 31

Describes the catalytic aspect of enzyme action Reveals the turnover number

Answer 31

Vmax

Question 32

This is a double reciprocal plot used to calculate Km and Vmax as well as to determine the mechanism of action of enzyme INHIBITORS

Answer 32

Lineweaver-Burke plot

Question 33

Derived from the reciprocal of the Michaelis Menten equation Gives the equation of a straight line

Answer 33

Lineweaver-Burke Plot

Question 34

Interferes with active site of enzyme so substrate cannot bind

Answer 34

Competitive inhibition

Question 35

Changes shape of enzyme so it cannot bind to substrate

Answer 35

Noncompetitive inhibition

Question 36

The structure of the inhibitor resembles the substrate

Answer 36

Competitive inhibition

Question 37

Km increases | Vmax constant

Answer 37

Competitive inhibition

Question 38

Competitive inhibitions aims to

Answer 38

overcome increased concentration of substrate

Question 39

Km constant | Vmax decreases

Answer 39

Non Competitive inhibition

Question 40

Aim of non competitive inhibition is

Answer 40

Reversible or irreversible binding depending on whether the inhibitor binds temporarily or indefinitely