Enzymes I+II- Lecture 8/31/21

Question 1

Elastase

Answer 1

A protease that destroys elastin, which destroys the lining of the lungs

Question 2

How can enzyme activity be deficient

Answer 2

Enzyme isn’t made
Enzyme is made but has a mutation that lowers activity
Insufficient substrate
inhibited

Question 3

Catalyst

Answer 3

Third party that alters the kinetics of a reaction without being altered itself

Question 4

Oxidoreductases

Answer 4

Catalyze an oxidation-reduction rxn, ex: NAD+->NADH

Question 5

Transeferases

Answer 5

Transfer of a chemical group ex: kinases

Question 6

Hydrolases

Answer 6

Lysis of water, ex: protease

Question 7

Lyases

Answer 7

A cleavage rxn not using water

Question 8

Isomerases

Answer 8

Change of a molecular configuration

Question 9

Ligases

Answer 9

Joining of two compounds ex: DNA poly

Question 10

Delta G

Answer 10

Change in free energy

Question 11

Spontaneous rxn

Answer 11

Has a negative delta G

Question 12

Gibbs free energy equations

Answer 12

DeltaG=DH-TDS

Question 13

Standard conditions for DGo

Answer 13

Certain temp, 1 M conc, except [H+] is pH of 7

Question 14

Gibbs free energy in not standard conditions

Answer 14

DG=DGo+RTlnQ

Question 15

Q

Answer 15

Q= [Products]/[reactants]

Question 16

Equilibrium

Answer 16

When DG=0

Question 17

Keq

Answer 17

Q at equilibrium

Keq=e>-DGo/RT

Question 18

When Q>Keq

Answer 18

The reaction goes in reverse

Question 19

When Q

Answer 19

Reaction proceeds forward, removal of product drives reaction forward

Question 20

Transition state

Answer 20

High energy intermediate, stabilization by catalyst allows for the activation energy to be lowered and the rxn to proceed faster

Question 21

Catabolism

Answer 21

The breakdown of energy yielding nutrients to gain energy in the form of ATP, NADH

Question 22

Anabolism

Answer 22

Using simple precursor molecules to build complex molecules needed for life, includes active transport and mechanical work

Question 23

Multibinding enzymes

Answer 23

Enzymes can bind more than one substrate, and often couple an exergonic rxn with an endergonic one

Question 24

Serine proteases

Answer 24

Proteolytic enzymes that catalyze peptide bond hydrolysis by using activated serine resides to add water and break the bond

Question 25

Active site

Answer 25

Usually a crevice on the surface of the enzyme where the substrate binds

Question 26

Velocity of an enzyme

Answer 26

The amount of product formed per unit time

Question 27

Vmax

Answer 27

The point at which adding more substrate does not lead to an increase in reaction velocity (adding more enzyme increases Vmax)

Question 28

Equation for velocity

Answer 28

V=Vmax[S]/(Km+[S])

Question 29

Km

Answer 29

The concentration of substrate when v=1/2Vmax

Question 30

What does Km tell us about enzyme affinity?

Answer 30

The lower the Km, the higher the affinity

Question 31

Kcat

Answer 31

A measure of enzymatic efficiency, Kcat=Vmax/the enzyme concentration, “turn over” number. Characteristic of an enzyme

Question 32

Lineweaver Burke plot

Answer 32

Linear derivation of MM plot, 1/v=(Km/Vmax)1/[S]+1/Vmax

Question 33

Vmax on LB plot

Answer 33

The Y intercept is 1/Vmax

Question 34

Km on LB plot

Answer 34

X intercept, -1/km

Question 35

Competitive inhibitor

Answer 35

Binds in the active site, increases Km but does not effect Vmax

Question 36

Non-competitive inhibitors

Answer 36

Binds to an allosteric site, Km is unaffective, Vmax is decreased

Question 37

Zymogens

Answer 37

The active site is not formed correctly until cleavage event

Question 38

A1-antitrypsin

Answer 38

Inhibits the elastase in the lungs, prevents lung degradation

Question 39

Protein phosphorylation

Answer 39

Enzymes can be phosphorylated to change the shape and therefore function

Question 40

Allosteric enzymes

Answer 40

Have t and r state, more sensitive to enzyme concentration

Question 41

Feedback loops

Answer 41

Final product can inhibit the first enzyme in a pathway

Question 42

Direct product inhibition

Answer 42

Inhibition of an enzyme by the direct product of that rxn.