Week 4

Question 1

Competitive Inhibitor

Answer 1

Vmax same, change in Km

Question 2

Uncompetitive Inhibitor

Answer 2

Change in Vmax and Km

Question 3

NonCompetitive Inhibitor

Answer 3

Change in Vmax, same KM

Question 4

Kd Equation

Answer 4

(Mb)(O2)/(MbO2)

Question 5

Kd Definition

Answer 5

Smaller Kd the greater affinity of the ligand for its protein. Dissociation

Question 6

Myoglobin

Answer 6

Higher affinity for oxygen
Acts as oxygen storage in tissue

Question 7

Hemoglobin

Answer 7

Acts as oxygen transporter through bliss
Exhibits cooperatively
Has quarternary structure

Question 8

Effects on Hb

Answer 8

Positive: CO and O2
Negative: 2,3 BPG, CO2, H+

Question 9

Bohr Effect

Answer 9

Concentration of CO2 increases, H+ ions increase

Question 10

Oxygen binding curve for fetal Hb lays where

Answer 10

To the left of

Question 11

Reversible Inhibitors

Answer 11

Competitive, Uncompetitive, and NonCompetitive

Question 12

Irreversible Inhibitors

Answer 12

Bind very tightly to active site
No products formed, shuts enzyme down
Powerful tools for elucidating the mechanisms of enzyme action

Question 13

Catalytic Triad

Answer 13

Asp, His, and Ser

Question 14

What stabilizes polypeptide

Answer 14

Oxyanion Hold

Question 15

Chymotrypsin Mechanism Steps

Answer 15

1. His extract H+ from Ser
2. Ser attacks peptide
3. Formation of Tetrahedral Intermediate
4. Tetrahedral Intermediate extracts H+ from His
5. Cleaved peptide 1 is free to leave
6. Cleaved peptide leaves and is replaced with water
7. Hid extracts H+ from water, OH attacks peptide bound to Ser.
8. H+ is extracted from His
9. Peptide 2 is free to leave

Question 16

Oxyanion Hole

Answer 16

Hydrogen bonding with backbone of peptide chain

Question 17

Heme

Answer 17

Prosthetic Group

Question 18

How is iron held

Answer 18

Iron is held in gene group by 6 coordinate covalent bonds from the 4 nitrogen’s in tetra pyrrole group

Question 19

How many coordination sites does iron give

Answer 19

6
4 are occupied by nitrogen’s in tetrapyrrole ring
5th is nitrogen from proximal histidine
6th is occupied by O2

Question 20

Fractional Saturation Equation, Y

Answer 20

Y = pO2/Kd + pO2

@ Y=1/2 Kd=O2

Question 21

Oxygen Binding with Iron

Answer 21

No O2 bound iron is larger than bound O2

Question 22

Bohr Effect

Answer 22

Stimulation of O2 release by CO2 and H+

Question 23

Shift Right

Answer 23

Negative Effect

Question 24

Shift Left

Answer 24

Positive Effect