Enzymes

Question 1

Enzyme

Answer 1

Biological catalyst

Question 2

Does a catalyst change the kinetics or thermodynamics (Delta H) of a reaction?

Answer 2

Delta H

Question 3

What doesnt a catatlyst change?

Answer 3

Delta H
Equilibrium constant
Delta G/Free Energy

Question 4

What does a catalyst change?

Answer 4

Lowers the free energy of activation

Question 5

Enzyme suffix

Answer 5

-ase

Question 6

Oxidoreductase

Answer 6

Catalyze oxidation-reduction reactions - transfer of electrons between biological molecules
Often have cofactors that carry electrons ( NAD+ or NADP+)

Question 7

Reductant

Answer 7

Electron donor

Question 8

Oxidant

Answer 8

Electron acceptor

Question 9

What kind of enzymes are oxidoreductase?

Answer 9

Dehydrogenase, reductase, oxidase

Question 10

Transferase

Answer 10

Catalyze the movement of a functional group from one molecule to another

Question 11

What kinds of enzymes are transferase?

Answer 11

aminotransferases, kinases

Question 12

Example of aminotransferase:

Answer 12

aspartate & a-ketoglutarate –>glutamate & oxaloacetate

Question 13

Kinase

Answer 13

Cataylze transfer of phosphate to another molecule

Question 14

Hydrolase

Answer 14

Catalyze breaking of a compound into two molecules using the addition of water

Question 15

What kinds of enzymes are hydrolase?

Answer 15

Phosphatase, Peptidases, nuclease, lipases

Question 16

Lyase

Answer 16

Catalyze the cleavage/synthesis of a single molcule into two products
Do not use water & don’t reduce/oxidizae
Often create double or cyclic bonds

Question 17

What kinds of enzymes are lyases?

Answer 17

Lyase, synthase

Question 18

Isomerase

Answer 18

Rearrange bonds within a molecule

Between stereoisomers & constitiutional isomers

Question 19

Ligases

Answer 19

Catalyze addition or synthesis reactions between large, similar molecules
Requires ATP
Nucleic aid synthesis & repair

Question 20

Enyzme Type Mnemonic

Answer 20

LI’L HOT

Question 21

Endergonic reaction

Answer 21

Requires energy

Delta G > 0

Question 22

Exergonic reaction

Answer 22

Spontaneous

Delta G < 0

Question 23

Apoenzyme

Answer 23

Enzymes without cofactors

Question 24

Holoenzymes

Answer 24

Enzymes with cofactor

Question 25

Prosthetic groups

Answer 25

Tightly bound cofactors necessary for enzyme function

Question 26

Cofactor

Answer 26

Generally inorganic molecules or metal ions (dietary minerals)

Question 27

Coenzymes

Answer 27

Small organic groups that are vitamins or derivatives of vitamins (NAD+, FAD+, coenzyme A)

Question 28

Saturation

Answer 28

When an enzyme is working at max velocity and cannot be increased by adding more substrate

Question 29

Michaelis-Menton Equation

Answer 29

v=Vmax [S]/Km + S

Question 30

Km

Answer 30

Michaelis constant-Substrate concentration at which half of the enzyme's active sites are full

Question 31

Km can used as a measure of

Answer 31

affinity of an enzyme for a substrate Higher Km=lower affinity Cannot be altered by concentration

Question 32

What is the slope of a Lineweaver-Burke plot

Answer 32

Km/Vmax

Question 33

What is the y-intercept of Lineweaver-Burke plot

Answer 33

1/Vmax

Question 34

What is the x-intercept of Lineweaver-Burke plot

Answer 34

-1/Km

Question 35

What does as sigmoidal shape on a Michaelis-Menton plot mean?

Answer 35

Cooperativity

Question 36

Why is there a sigmoidal shape in cooperativity?

Answer 36

As one subunit is bound with substrate, the next subunit has a more increased likelihood of wanting that conformation as well

Question 37

What things mainly affect enzyme activity/rate/velocity

Answer 37

pH, temperature & salinity

Question 38

Optimal human body temperature

Answer 38

98.6 F or 37 C

Question 39

Affect of temperature on enzymes

Answer 39

Activity increases every 10 C, until optimal temperature

Question 40

Optimal blood

Answer 40

pH 7.4

Question 41

What does a competitive inhibitor do to the Km value?

Answer 41

Increases it because more substrate will be needed to reach half the maximum velocity

Question 42

What does competitive inhibitor do to Vmax value?

Answer 42

Nothing, same y-intercept

Question 43

What does a noncompetitive inhibitor do to Vmax?

Answer 43

Decreases it because there is less enzyme available to react

Question 44

What does a noncompetitive inhibitor do to Km?

Answer 44

Doesnt change, any copies of enzyme still maintain same affinity for substrate

Question 45

Mixed inhibition

Answer 45

Inhibitor can bind to enzyme or enzyme-substrate complex | Binds at allosteric site

Question 46

Mixed inhibition affects:

Answer 46

Km: Binds to enzyme- increases Km (lower affinity) Binds to enzyme-substrate complex- lowers Km (higher affinity) Vmax decreases

Question 47

Uncompetitive Inhibition

Answer 47

Bind only to enzyme-substrate complex and lock them together | Bind at allosteric site

Question 48

Uncompetitive inhibition affects:

Answer 48

Lower Km & Vmax

Question 49

Allosteric Enzyme

Answer 49

Have active & allosteric sites that have allosteric inhibitors or activatoirs

Question 50

Zymogen

Answer 50

Secreted inactive and contain catalytic domains &regulatory domains to turn themselves on/off

Question 51

Velocity of the reaction rate equation

Answer 51

v= vmax[S]/Km + [S}