Lecture 12

Question 1

protein studies

Answer 1

• isolate proteins from samples
• purify proteins from isolations
• visualize and size
• identify
• use/study

Question 2

What leads to 2 and 3 degree structures of proteins?

Answer 2

R group interactions

Question 3

Charge of some R groups is….

Answer 3

pH dependent

Question 4

hydrophobic / non polar R groups

Answer 4

tend to fold internally

Question 5

hydrophilic /polar R groups

Answer 5

tend to fold externally (to interact with water)

Question 6

enzyme

Answer 6

a protein or RNA that acts as a catalyst for a chemical reaction

Question 7

Enzymes make reactions…

Answer 7

more favourable at physiological conditions

Question 8

enzyme specificity

Answer 8

a product of having the right shape to hold the substrate(s) and a catalytic center to facilitate the reaction

Question 9

enzyme specificity may require…

Answer 9

cofactors like organic molecules (coenzymes) or metal ions

Question 10

A–>B

Answer 10

isomerization

Question 11

A+B–>C

Answer 11

condensation

Question 12

A–>B+C

Answer 12

lysis

Question 13

A+B–>C+D

Answer 13

complicated

Question 14

reaction rate/velocity

Answer 14

v=(-)delta[S]/delta t

v=(+)delta[P]/delta t

Question 15

Initial Velocity

Answer 15

measured quickly and for a short period of time (before 10% of reactants are used up)

Question 16

rate can be limited by…

Answer 16

availability of substrate and by production of product

Question 17

Under optimal conditions and with excess substrate, limiting step is…

Answer 17

how fast enzyme can catalyze (ES–>E+P)

Question 18

substrate conc and initial velocity relationship

Answer 18

as substrate conc. increases, initial velocity increases

Question 19

Michaelis-Menten Equation

Answer 19

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

Question 20

Km

Answer 20

(Michaelis constant) [S] when Vo = 1/2Vmax

Question 21

Km is often neat..

Answer 21

the physiological conc. of the substrate in the target cell

Question 22

normal (alcohol)

Answer 22

rate from ethanol to acetaldehyde is the same as acetaldehyde to acetic acid

Question 23

allergic (alcohol)

Answer 23

acetaldehyde accumulates because rate is different

Question 24

Vmax

Answer 24

the enzyme rate as we increase [S]

Question 25

turnover number

Answer 25

-kcat=vmax/[E]T

Question 26

Lineweaver-Burk

Answer 26

uses double reciprocal of rate and conc. to place Vmax and Km on X and Y intercepts

Question 27

Km values can be used to..

Answer 27

investigate affinity of an enzyme for a substrate and compare reaction rates in more complicated living systems

Question 28

competitive inhibition

Answer 28

a compound binds to active site of enzyme and excludes reactant
-lower affinity of enzyme

Question 29

uncompetitive inhibition

Answer 29

[up=up] a compound binds the ES complex and slows transition to EP

Question 30

non-competitive inhibition

Answer 30

a compound binds the enzyme and change shape of active site