Last prep

Question 1

What subunit is myoglobin made of

Answer 1

an alpha helix

Question 2

Myoglobin serves as an oxygen

Answer 2

storage system

Question 3

myoglobin binds oxygen tightly/weakly

Answer 3

tightly

Question 4

Hemoglobin serves as an oxygen

Answer 4

delivery system

Question 5

Porphyrin is aka

Answer 5

heme

Question 6

is heme covalently bound

Answer 6

no

Question 7

what interactions does heme have

Answer 7

distal histidine binds with Fe(II), bent with O2

Question 8

why does myoglobin have a bent configuration with O2?

Answer 8

If it doesn’t, it’d oxidize Fe, making it unusable

Question 9

If oxygen steals electrons from Fe(II), what happens?

Answer 9

O2 -> O2-, a toxic radical. Fe(II)->Fe(III), useless.

Question 10

Myoglobin’s binding curve is X, which is typical for molecules with X

Answer 10

hyperbolic, one binding site

Question 11

YO2

Answer 11

% of Mb bound to O2

Question 12

pO2

Answer 12

O2 concentration

Question 13

higher kd

Answer 13

weaker bing

Question 14

Is myoglobin commonly needed for oxygen?

Answer 14

no

Question 15

Hemoglobin strongly/weakly binds o2

Answer 15

weakly

Question 16

is hemoglobin hit hard by lack of o2

Answer 16

yes

Question 17

hemoglobin’s binding curve is

Answer 17

sigmoidal

Question 18

hemoglboin has X subunits

Answer 18

4

Question 19

are alpha and beta subunits similar

Answer 19

yes

Question 20

how does binding of o2 for hemoglobin work for each subunit

Answer 20

o2 binding for each unit gets easier and easier

Question 21

Sigmoidal binding curves imply…

Answer 21

1. Multiple binding sites
2. Binding of one site affects the other

Question 22

Does multiple binding sites mean the binding is cooperative?

Answer 22

no

Question 23

Iron in hemoglobin sits on X plane when O2 binds- Sjrinks and moves into its plane

Answer 23

porphyrin

Question 24

How does O2 binding to hemoglobin work?

Answer 24

1. O2 binds to iron and moves down .6 angstroms
2. alpha helix goes with (because it’s boudn to histidine) and pulls aspartic acid with it.
3. Histidine is pulled from carboxylic acid and loses its proton, become normal histidine

Question 25

When O2 binds to hemoglobin, X is released

Answer 25

H+

Question 26

Oxygen binding to hemoglobin means O2 saturation affects local X- meaning X is X sensitive

Answer 26

pH, Hb affinity, pH

Question 27

What happens if H+ concentration increases? (to hemoglobin)

Answer 27

H+ will force its way back on

Question 28

CO2 + H2O ->

Answer 28

HCO3- + H+

Question 29

HHb + O2 ->

Answer 29

HbO2 + H+

Question 30

More protons= X CO2

Answer 30

More

Question 31

Why is there more H+ with more CO2

Answer 31

Increating H+ concentrations by reacting with water to make HCO3

Question 32

What happens when CO2 reacts with NH2 in Hb's N terminus?

Answer 32

It'll lose a proton.

Question 33

Binding curve of Hb shifts X with more protons

Answer 33

right

Question 34

Shifting of binding curve of Hb means there's X O2 needed to bind Hb because it gets released X easily

Answer 34

more, more

Question 35

X is a nanomechanical machine that senses CO2 and adjusts its affinity for O2 accordingly

Answer 35

Hb

Question 36

Conc and summary slide

Question 37

If X were mutated, hemoglobin coudln't bind oxygen properly and binding wouldn't be pH dependent

Answer 37

Histidine

Question 38

BPG binds to Hb X tightly than HbO2

Answer 38

More

Question 39

BPG mimics the effects of X pH

Answer 39

Low

Question 40

What makes up most of RBC volume?

Answer 40

Hb- with a little carbonic anhydrase

Question 41

What does carbonic anhydrase do

Answer 41

tweak pH slightlyW

Question 42

What's up with hemoglobin in SCA?

Answer 42

Easily crystallized

Question 43

What's the mutation in hb that causes SCA on a cellular level?

Answer 43

Forms long crystals that distors the cell into sickle shape, affecting capillaries. G

Question 44

SCA mutation on an AA level-

Answer 44

Glu -> Val Strong hydrophobic interaction lets Hb stack

Question 45

Catalysis

Answer 45

rate of reaction

Question 46

Delta G

Answer 46

difference in energy between beginnint and end state

Question 47

k=Ae^(-Ea/RT)

Answer 47

As energy of activation increases, rate constant decreases exponentioally. Reaction barrier only needs to be slightly changed for massive gains

Question 48

Protease

Answer 48

Enzyme that cuts other enzymes

Question 49

Serine protease

Answer 49

An enzyme that folds so serine is deprotonated and OH does a nucleophilic attack

Question 50

What activates seine in Sering Protease

Answer 50

Catalytic triad. Held close together by nature of the protein

Question 51

Serine Protease's mechanism

Answer 51

1. Histidine has N (3) that steals Serine's H+, H becomes a strong base. 2. Aspartic acid pulls H+ from imidazole ring, increasing electron density 3. Serine is deprotonated and attacks protein. 4. C=O in backbone is removed from rest of molecule 5. Water attacks C on Ester.