Enzymes & Inhibition

Question 1

Allosteric effector

Answer 1

Binds at the allosteric site and induces a change in the conformation of the enzyme so the substrate can no longer bind to the active site. Displays cooperativity, so it does not obey MichaelisMenten kinetics.

Question 2

Hill coefficient = 1

Answer 2

No cooperativity (normal MM kinetics); Substrate binding doesn’t affect affinity

Question 3

this enzyme Moves a functional group from one molecule to another

Answer 3

transferase

Question 4

Answer 4

competitive inhibition

Question 5

Hill coefficient

Answer 5

measure of cooperatively (ie Hb, where you see sigmoidal kinetic curves that don’t follow Michaelis-Menten)

Question 6

hydrolysis of fats is included in this class of enzymes

Answer 6

lyases

Question 7

in uncompetitive inhibition, Vmax…

Answer 7

decreases

Question 8

catalyzes cleavage without H2O or the transfer of electrons

Answer 8

lyases

Question 9

On the LWBP, competitive inhibition effects the X-intercept by…

Answer 9

increases it (moves toward the origin)

Question 10

Prosthetic groups

Answer 10

tightly bound cofactors or coenzymes that are necessary for enzyme function

Question 11

Hill coefficient > 1

Answer 11

positive cooperativity; Substrate binding increases affinity

Question 12

dehydrogenase, oxidase, and peroxidase are all ____ enzymes

Answer 12

oxidoreductases

Question 13

this type of enzyme is known for addition/synthesis reactions and usually requires ATP

Answer 13

ligases

Question 14

Glycosylation

Answer 14

covalent modification w/ carbohydrate (adding sugar)

Question 15

phosphotransferases that add a phosphate group, usually with ATP as a donor

Answer 15

kinases

Question 16

On the LWBP, competitive inhibition effects the Y-intercept by…

Answer 16

no change

Question 17

Enzyme-catalyzed reactions w/ high enzyme-substrate affinity will reach the ½Vmax benchmark at a (lower/higher) [substrate] aka have a (lower/higher) Km; lower enzyme-substrate affinities → needing a (lower/higher) [substrate] to reach ½Vmax (have a (lower/higher) Km).

Answer 17

Enzyme-catalyzed reactions w/ high enzyme-substrate affinity will reach the ½Vmax benchmark at a lower [substrate] aka have a lower Km; lower enzyme-substrate affinities → needing a higher [substrate] to reach ½Vmax (have a higher Km).

Question 18

in noncompetitive inhibition, Km…

Answer 18

doesn’t change

Question 19

these enzymes introduce a phosphate group into an organic molecule (glucose)

Answer 19

phosphorylase

Question 20

this type of enzyme joins two large biomolecules, often of the same type

Answer 20

ligases

Question 21

cofactor

Answer 21

Inorganic ions and metal cation; like Fe²⁺ and Mg²⁺; directly involved in the enzyme’s catalytic mechanism

Question 22

If Vmax increases, the paramater values ______. The intercept _____ and moves ______ the origin.

Answer 22

If Vmax increases, the paramater values doubles. The intercept decreases (becomes less +) and moves towards the origin.

Question 23

this type of enzyme is used to create bonds b/t Okazaki fragments

Answer 23

ligases

Question 24

In this type of inhibition, the inhibitor is similar to the substrate and binds @ the active site

Answer 24

competitive inhibitor

Question 25

In enzyme kinetics, calculate v₀

Answer 25

Question 26

this class of enzymes includes the interconversion of isomers, constitutional & stereoisomers

Answer 26

isomerases

Question 27

in this type of inhibition, the inhibitor binds w/ unequal affinity to the enzyme and the enzyme-substrate complex

Answer 27

mixed inhibition

Question 28

a synthase could also be a ______ but a synthetase must be a \_\_\_\_\_

Answer 28

a synthase could also be a synthase but a synthetase must be a ligase

Question 29

Coenzyme

Answer 29

Organic molecule; like heme, NAD⁺ & Coenzyme A. Many are derived from vitamins

Question 30

heterotrophic effector

Question 31

where is the binding site in noncompetitive inhibition

Question 32

In this type of inhibition, the inhibitor binds with equal affinity to the enzyme and the enzyme-substrate complex

Answer 32

noncompetitive inhibition

Question 33

Irreversible inhibition:

Answer 33

alters the enzyme so that the active site is unavailable for a prolonged duration or permanently; new enzymes molecules must be synthesized for the rxn to occur again

Question 34

On the LWBP, uncompetitive inhibition effects the X-intercept by...

Answer 34

decreases it (moves away from the origin)

Question 35

If the mixed inhibitor ends up binding more readily to the _____ Km is lower

Answer 35

If the mixed inhibitor ends up binding more readily to the enzyme-substrate complex Km is lower

Question 36

Enzyme kinetics equaiton, what does v = ?

Answer 36

Question 37

On the LWBP, uncompetitive inhibition effects the Y-intercept by...

Answer 37

increases (moves away from the origin)

Question 38

where is the binding site in competitive inhibition?

Answer 38

active site

Question 39

these remove a phosphate group

Answer 39

phosphatase

Question 40

in mixed inhibition, Km...

Answer 40

increases or decreases

Question 41

in competitive inhibition, Km...

Answer 41

increases

Question 42

Km

Answer 42

The [S] at which an enzyme runs at half its Vmax.

Question 43

transaminase is an example of a ______ enzyme

Answer 43

transferase

Question 44

nucleic acid synthesis uses these kind of enzymes

Answer 44

ligases

Question 45

On the LWBP, mixed inhibition effects the X-intercept by...

Answer 45

increases or decreases it (moces towards or away from the origin)

Question 46

how does increasing the amount of substrate affect Vmax

Answer 46

increasing substrate = increases Vmax

Question 47

On the LWBP, mixed inhibition effects the Y-intercept by...

Answer 47

increases (moves away from the origin)

Question 48

isomerases include

Answer 48

oxidoreductases, transferases, lyases

Question 49

Hill coefficient n \< 1

Answer 49

negative cooperativity; Substrate binding decreases affinity for subsequent substrate

Question 50

these generates either a double bound or ring structure

Answer 50

lyases

Question 51

Cleavage with H₂O = ____ enzyme

Answer 51

hydrolases

Question 52

Answer 52

Noncompetitive inhibition

Question 53

aminotransferase is an example of a _____ enzyme

Answer 53

transferase

Question 54

On the LWBP, noncompetitive inhibition effects the X-intercept by...

Answer 54

no change

Question 55

In this type of inhibition, the the inhibitor binds only with the enzyme-substrate complex

Answer 55

uncompetitive inhibition

Question 56

On the LWBP, noncompetitive inhibition effects the Y-intercept by...

Answer 56

increases (moves away from the origin)

Question 57

If the mixed inhibitor ends up binding more readily to the _____ Km is higher

Answer 57

If the mixed inhibitor ends up binding more readily to the enzyme Km is higher

Question 58

in mixed inhibition, Vmax...

Answer 58

decreases

Question 59

where is the binding site in mixed inhibition

Answer 59

allosteric site

Question 60

These only require 1 substrate when cleaving but 2 for the reverse

Answer 60

lyases

Question 61

Vmax

Answer 61

The max rate (enzyme velocity) at which an enzyme can catalyze a reaction; when all enzyme active sites are saturated with substrate

Question 62

in uncompetitive inhibition, Km...

Answer 62

decreases

Question 63

in competitive inhibition, Vmax...

Answer 63

doesn't change

Question 64

If Km increases, the paramater values \_\_\_\_\_\_. The intercept _____ and moves ______ the origin.

Answer 64

If Km increases, the paramater values **doubles**. The intercept **increases (becomes less negative)** and moves **towards** the origin.

Question 65

Suicide inhibitor:

Answer 65

A substrate analogue that binds irreversibly to the active site via a covalent bond.

Question 66

homotrophic effector

Answer 66

An allosteric regulator that is also the substrate.

Question 67

Answer 67

uncompetitive inhibition

Question 68

in noncompetitive inhibition, Vmax...

Answer 68

decreases

Question 69

phosphatase, peptidase, nuclease, lipase = all are ____ enzymes

Answer 69

hydrolases

Question 70

methyltransferase is an example of a _____ enzyme

Answer 70

transferase

Question 71

where is the binding site in uncompetitive inhibition

Answer 71

enzyme-substrate complex