This slide is for bachelor level medical students of any program who wants to take brief ideas about ongoing metabolism in RBC and WBC.

1. Metabolism in RBC &
WBC
Binaya Tamang
UCMS- Bhairahwa

2. Metabolism in RBC

3. Cytoskeletal protein: Biconcave shape?

4. lack of these protein; hemolytic anemia

5. Advantages of biconcave
• Higher ratio of surface area to volume
• To fold over and squeeze through narrow capillaries
• Minimizes distance to be traversed, efficient gas exchange
between capillary walls
• Rapidly moving Rbc( up to 2mm/s)

6. • Highly dependent upon glucose as its energy source.
• RBC memb. has high affinity glucose transporters.
• facilitated diffusion
• the erythrocyte is capable of glucose uptake by facilitated
diffusion b/c of
1. its low intracellular glucose concentration and
2. the presence of glucose carrier protein, or glucose
transporter GLUT;
GLUT1 in erythrocyte
Glucose, Glut in RBCs

7. Pathways of glucose utilization
• RBC utilize glucose via:-
» Anaerobic glycolysis
» luebering rapoport cycle
» HMP Shunt

8. ATP produced is utilized for
• Maintain its biconcave shape
• Transport ions ( e.g. Na/K ATPase)
• Anion exchange protein
• Water in and out of cells.
• ( overall survival of RBCs)

9. • Yields 2,3-BPG
• It helps in O2 unloading at tissue.
• At low pO2 at tissue, Hb has more affinity to 2,3-BPG.
• Due to ↑ concentration of 2,3-BPG in tissue, Hb binds 2,3-
BPG & leads to unloading of O2.
• Under hypoxic conditions, Anemic condition, high altitude
• To differentiate hemolytic anemia between hexokinase and
pyruvate kinase deficiency (glucose is not phosphorylated,
hence the synthesis & concentration of 2,3-BPG are low in
RBC)
Luebering Rapoport cycle in RBC

11. • Due to absence of mitochondria, anaerobic glycolysis occurs in
RBC.
Glucose
Anaerobic glycolysis 2 ATP
Lactate
↓
Cori’s cycle
Anaerobic glycolysis in RBC

13. • Yields NADPH and ribose
• What are its importance?
• G6PD deficiency anemia. Explain.
• First let us know the importance of reduced glutathione.
HMP Shunt in RBC

14. Imp: Generation of reduced Glutathione
• Role of GSH in RBC
– Maintains integrity of RBC membrane.
– -SH of GSH is used to reduce peroxides (ROS).

15. G6PD deficiency anemia

16. G6PD deficiency anemia: hypersensitive conditions
• X linked recessive
• Tropical Africa, Mediterranean, certain part of south asia
• Eg. Sulfanomide drugs, antimalarial primaquine, proxidant
containing food ( vicia faba)
• Exposure to chemicals like naphthalene.
• RBCs cant combact with such episodes of oxidative stress and get
lysed leading anemia.

17. Methemoglobin
• The ferrous iron of hemoglobin is susceptible to oxidation by
superoxide and other oxidizing agents, forming
methemoglobin, which cannot transport oxygen.
• Small quantity of methemoglobin is reduced back to the
Fe2+ state by met-hb reductase enzyme system using
NADH and cytochrome b5.

18. Maintenance of HB in Ferrous (Fe2+) state
• NADH prevent accumulation of Met-Hb.
• Met-Hb (Fe3+) can’t transport O2.
• 75% using NADH and cytochrome b5
• 20% is due to NADPH dependent system
• Glutathione dependent met-Hb reductase accounts for rest 5% activity.
Methemoglobinemia
Inherited : deficiency of methemoglobin reductase, AR , Hb M,
Acquired: certain drugs (eg, sulfonamides) or chemicals (eg, aniline)
Bluish coloration called cyanosis.

19. • Synthesis of glycogen, FA, protein, & nucleic acids doesn’t
occur in RBC.
• Some lipids (eg, cholesterol) in RBC memb. can exchange
with corresponding plasma lipids.
• During RBC degradation,
– Globin is degraded to amino acids (reutilized in body)
– Iron is released from heme & reutilized
– Tetrapyrrole of heme is converted to bilirubin,

20. • RBC can’t synthesize Protein
– Devoid of internal organs to deliver max of O2 to tissue
– Reticulocytes are active in protein synthesis.
– Mature RBC can’t synthesize protein.
Reticulocytes enter circulation
↓
Lose intracellular organelles within 24hr
[Ribosomes, Mitochondria]
↓
Become young RBC
↓
lose their ability to synthesize protein

21. BIOCHEMISTRY OF ABO BLOOD GROUP
• At least 21 human blood group systems
• ABO, Rh (Rhesus), and MN systems.
• first discovered by Landsteiner
• ABO Substances Are Glycosphingolipids & Glycoproteins
• H substance itself is formed by the action of a
fucosyltransferase, which catalyzes the addition of the
terminal fucose in α1 → 2 linkage onto the terminal Gal
residue of its precursor:

22. Contd….
• A substance contains an additional GalNAc
(immunodominant sugar).
• B substance an additional Gal (immunodominant sugar).

24. Metabolism in WBC

25. • Active glycolysis
• Active pentose phosphate pathway
• Moderate oxidative phosphorylation
• Rich in lysosomes (degradative enzymes)
• Contain certain unique enzymes (eg, myeloperoxidase &
NADPH-oxidase)
• Also has role in acute inflammatory response.
Metabolism in WBC

26. Respiratory burst of phagocytic cells
• Involves NADPH oxidase and helps kills bacteria.
• When neutrophils and other phagocytic cells engulf bacteria,
they exhibit a rapid increase in oxygen consumption known as
the respiratory burst.

29. Chronic granulomatous disease

30. Summary of important aspects of
the metabolism of the red blood cell.

31. Thank you