11-21 L3 RBC metabolism

Question 1

What does the distal and proximial His do (and where is it located)

Answer 1

• Proximal His (93)
  
  • F8
  • attaches to the iron
• Distal His (64)
  
  • E7
  • reduces space forcing binding molecule to attach at an angle

Question 2

What is the difference between Mb and Hb?

Answer 2

• Mb
  
  • O2 binding non-coorperative
  • independent of pH, CO2, and 2,3 BPG
• Hb
  
  • O2 binding cooperative
  • dependent of pH, CO2, and 2,3 BPG

Question 3

Why does FHb have low affinty for 2,3 BPG

Answer 3

• Due to a sub of 1 of the 4 His in Heme
• His (143)–> Ser (143)

Question 4

Define the 3 aspects of the bohr affect and what does it cause the O2 to do?

Answer 4

• pH falling
• [H+]
• [CO2] increases

results: Hb releasing more O2

Question 5

What is the role of HMP shunt

Answer 5

• to generate NADPH (oxidative reactions)
• interconvert 5 and 6 carbon sugars (non-oxidative reactions)

Question 6

desrcibe two enzymes involved in Non-oxidatiative rxn (HMP shunt)

Answer 6

• TK (transketolase):
  
  • Ketose –> aldose
  • 2 carbons units from a ketose to an aldose
• TA: transaldolase transfer
  
  • Aldose–> ketose
  • 3 carbons units from a ketose to an aldose

Question 7

How does the RBC protect itself from oxidation?

describe the pathway

Answer 7

Glutathione

sacrifices itself:

is normally in a reduced state, which is preferentially oxidized by the oxidizing agnets instead of the RBCS

Question 8

When is G6PDh def seen?

Answer 8

• under conditions of oxidative stress
  
  • eating fava beans
  • anti-malarial drugs

Question 9

What is an advantage to the G6PDH?

Answer 9

• resistance ot malaria