Lecture 9.22.14 (Ch.8 Enzyme Kinetics)

Question 1

What are enzymes?

Answer 1

proteins that catalyze reactions

Question 2

Each enzymes is…..

Answer 2

unique
catalyze specific reaction
speed up reactions

Question 3

What attracts the enzyme to the substrate?

Answer 3

Intermolecular Forces

Question 4

When the S binds to the E…

Answer 4

conformational change
stabilize transition state
create environment for the reaction

Question 5

Cofactor

Answer 5

any molecule that aids in catalysis

Question 6

What are the two types of cofactors?

Answer 6

Coenzymes & prosthetic groups

Question 7

coenzyme

Answer 7

nonprotein organic
aids in catalysis
binds with IMF

Question 8

prosthetic group

Answer 8

nonprotein organic
aids in catalysis
binds with covalent bond

Question 9

Enzyme with cofactor?

Answer 9

holoenzyme

Question 10

Enzyme without cofactor?

Answer 10

apoenzyme

Question 11

6 Types of Reactions

Answer 11

oxidoreductase
transferase
hydrolase
lyase
isomerase
ligase

Question 12

oxidoreductase

Answer 12

catalyze redox reactions

typically use NAD & FAD

Question 13

transferase

Answer 13

transfer a functional group

2 reactants= 1 product

Question 14

hydrolase

Answer 14

use H2O to break covalent bond (hydrolyze covalent bond)

Question 15

lyase

Answer 15

break/make covalent (C=C) bond without H2O

Question 16

isomerase

Answer 16

creates an isomer (molecule w/same empirical formula, but arranged differently)

Question 17

ligase

Answer 17

make covalent bond (2substrates) with the use of an energy source (ATP)

Question 18

2 theories of enzyme kinetics?

Answer 18

lock & key

induced fit

Question 19

Lock & Key Theory

Answer 19

S binds to E like a key fits a lock

Question 20

Induced Fit Theory

Answer 20

S bind to E, but “fits” to accommodate the transitional state (a conformational change occurs)

Question 21

How do enzymes speed up catalysis?

Answer 21

by lowering the activation energy

Question 22

What are the two things we need to know about enzymes?

Answer 22

How good S binds?

How good is E at producing E+P

Question 23

K1

Answer 23

association of S to E

Question 24

K-1

Answer 24

disassociation of S from E

Question 25

K2

Answer 25

release of product

Question 26

First order

Answer 26

rate (V) depends on [S]

linear line

Question 27

Zero Order

Answer 27

rate (V) is independent of [S]

horizontal line

Question 28

During a conformational change…

Answer 28

enzyme changes shape when substrate is bound to it

• creates a tighter induced fit
• bring chemical groups into position to catalyze the rxn
• create conditions for favorable reactions

Question 29

Enzyme Kinetics can tell us? (5)

Answer 29

concentration of enzyme (by activity)
purity (specific activity)
catalytic efficiency
specificity for different substrates
effect of inhibitors

Question 30

If the enzyme binds in the lock and key fashion…

Answer 30

the reaction will not proceed forward