Metabolism of carbohydrates

1. GLYCOLYSIS
Biochemistry II
Lecture

2. SUMMARY
1. THE REACTIONS OF GLYCOLYSIS
• Preparatory phase
• Payoff phase
2. OXIDATIVE FATES OF PYRUVATE
• Anaerobic Glycolysis
• Aerobic Glycolysis
3. OTHER FUNCTIONS OF GLYCOLYSIS

3. BIBLIOGRAPHY
. Lehninger. Biochemistry.
• Harpers Illustrated Biochemistry, 30 th edition
(2015)
• M N Chatterjea, Rana Shinde. Textbook of Medical
Biochemistry, 8th edition.(2012), chapter 36.
• Harrisons Principles of Internal Medicine, 19 th
edition (2015)
• D M.Vasudevan. Textbook of Biochemistry for
Medical Students, 6 th edition.(2011), chapter 27.

4. WAITING ROOM
A 60-year-old man is admitted to the
hospital emergency room with very low
blood pressure (80/40 mm Hg) caused by
an acute hemorrhage from a previously
diagnosed ulcer of the stomach.
He is also known to have chronic
obstructive pulmonary disease (COPD) as
a result of 42 years of smoking two packs
of cigarettes per day.

5. WAITING ROOM
A battery of laboratory tests are ordered,
including venous hemoglobin, hematocrit, and
lactate levels, and arterial blood pH, partial
pressures of oxygen (pO2) and carbon dioxide
(pCO2), bicarbonate, and oxygen saturation.
Results show that the hemorrhaging and
COPD have resulted in hypoxemia, with
decreased oxygen delivery to his tissues, and
both a respiratory and metabolic acidosis.

7. THE REACTIONS
OF GLYCOLYSIS

11. Preparatory Phase

12. HEXOKINASE

13. PHOSPHOHEXOSE ISOMERASE

14. PHOSPHOFRUCTOKINASE 1
MAIN REGULATION POINT IN GLYCOLYSIS

15. PHOSPHOFRUCTO KINASE 1
ALLOSTERIC REGULATION
• POSITIVE EFECTORS
– AMP
– Fructose 2,6-biphosphate
• NEGATIVE EFECTORS
– ATP
– Citrate

16. ALDOLASE

17. TRIOSA PHOSPHATE
ISOMERASE

20. Payoff phase

21. GLYCERALDEHYDE-3-P
DEHYDROGENASE

22. PHOSPHOGLYCERATE
KINASE

23. PHOSPHOGLYCERATE MUTASE

24. ENOLASE

25. PYRUVATE KINASE
SECONDARY REGULATION POINT

26. PYRUVATE KINASE
ALLOSTERIC REGULATION
• POSITIVE EFFECTORS
– Fructose - 1,6 - bisphosphate
• NEGATIVE EFFECTORS
– ATP

27. OXIDATIVE FATES
OF PYRUVATE
Anaerobic Glycolisis

29. LACTATE
DEHYDROGENASE
LDH

30. NADH REOXIDATION

33. ETHANOL
FORMATION
• Pyruvate
decarboxylase
• Alcohol
dehydrogenase
(ADH)

34. THIAMINE PYROPHOSPHATE

37. OXIDATIVE FATES
OF PYRUVATE
Aerobic Glycolisis

40. GLYCEROL-3-P SHUTTLE

41. MALATE-ASPARTATE
SHUTTLE
Malate Malate
2 NADH NADH

42. OTHER FUNCTIONS OF
GLYCOLYSIS

44. WAITING ROOM
A 60-year-old man is admitted to the
hospital emergency room with very low
blood pressure (80/40 mm Hg) caused by
an acute hemorrhage from a previously
diagnosed ulcer of the stomach.
He is also known to have chronic
obstructive pulmonary disease (COPD) as
a result of 42 years of smoking two packs
of cigarettes per day.

45. WAITING ROOM
His plasma lactic acid level was elevated and his
arterial pH was low because the severe reduction
in the amount of oxygen delivered to tissues for
cellular respiration (hypoxemia).
Several concurrent processes contributed to this
oxygen lack. The blood loss led to reduced delivery
of oxygen to his tissues, as well as the marked
reduction in the number of red blood cells in his
circulation. The preexisting chronic obstructive
pulmonary disease (COPD) decreases his
ventilation, and, therefore, the transfer of oxygen to
his blood.

46. CONCLUSIONS
1. Describe the main features of each
phase of glycolysis.
2. Pyruvate is the major product in
glycolysis. Which metabolic options it
has and in which conditions each one?
3. Mention other biological functions of
glycolysis.