1. Chapter 5 Carbohydrate Metabolism

2. Lecture 1 Function of carbohydrate
Lecture 2 The classification of carbohydrates
Lecture 3 Glycolysis
Lecture 4 The fates of pyruvate
Lecture 5 Gluconeogenesis
Lecture 6 The pentose phosphate pathway of
glucose oxidation
Lecture 7 Citric acid cycle

3. Lecture 1 Function of carbohydrate
Chapter 8 Carbohydrates

4. What are Carbohydrates (saccharides) ?
Carbohydrate is an organic compound with the general formula Cm(H2O)n, which consists of carbon, hydrogen and oxygen, the last two in the 2:1 atom ratio. Carbohydrates are hydrates of carbon, hence their name.
Carbohydrate, (C-H2O)n = “Carbon + Water”

5. Where are Carbohydrates? Function of Carbohydrates ?

6. Upland cotton produces the most widely used
natural fibers, cellulose (polysaccharide)
Cellulose:
the most abundant organic
compounds in the biosphere
1015 kg of cellulose is
synthesized and degraded
on earth each year
cellulose【纤维素】 polysaccharide【多糖】

7. Carbohydrates in food are important sources of energy.

8. Energy sources and structural elements
Cell wall
Energy sources

9. Energy sources and structural elements
Flexor muscle屈肌
Extensor muscle伸肌
Exoskeleton (cuticle)外骨骼（角质层）
Joint关节

10. Bioactive substance——Glycoproteins and Glycolipids

11. Structure (cotton fibers: cellulose ) Building blocks
Function of Carbohydrates
Source of energy
Structure (cotton fibers: cellulose )
Building blocks
Cellular recognition
cellulose【纤维素】

12. Lecture 2 The classification of carbohydrates （Saccharides ）
monosaccharide（单糖）
oligosaccharide（寡糖）
polysaccharide（多糖）

13. 1 Monosaccharide The generic name of the simplest carbohydrates.
Monosaccharides can not be hydrolysised to give smaller carbohydrates.
最简单的糖，不能被水解为更小的单位。

14. Monosaccharides can be classified according to the number of carbons:
Triose carbons
Tetrose 4 carbons
Pentose 5 carbons
Hexose 6 carbons
Heptose 7 carbons
triose【丙糖】 carbons
tetrose 【丁糖】 4 carbons
pentose【戊糖】 5 carbons
hexose【己糖】 6 carbons
heptose【庚糖】 7 carbons

15. Glucose , fructose , galactose, mannose
Important hexose :
Glucose , fructose , galactose, mannose
Important hexose【己糖】：
glucose【葡萄糖】, fructose【果糖】, galactose【半乳糖】, mannose【甘露糖】【-D-吡喃葡萄糖】【-D-呋喃果糖】

16. Pentose：
D-Ribose
【核糖】
【2-脱氧核糖】

17. 2 Oligosaccharide
Any molecule that contains a small number (2 to about 20) of monosaccharide residues connected by glycosidic linkages.
【寡糖】【糖苷键】由2-20个单糖通过糖苷键连成的糖类物质

18. Oligosaccharide
Maltose 1 4
Maltose【麦芽糖】葡萄糖-α,β(1→4)-葡萄糖苷

19. Sucrose It is formed by plants but not by animals. 2 1
Sucrose【蔗糖】植物体内糖的运输形式Sucrose contains no free anomeric carbon atom. Therefore it’s a nonreducing sugar.
anomeric carbon atom【异头碳原子】.
nonreducing 【非还原性】 sugar.葡萄糖-α,β(1→2)-果糖苷

20. Lactose Lactose occurs naturally in milk but rarely in plants.
Lactose 【乳糖】（milk sugar）
存在乳汁、花粉管及微生物中
Lactose occurs naturally in milk but rarely in plants.

21. Cellobiose
Cellobiose【纤维二糖】葡萄糖-β(1 →4)葡萄糖苷，人体无法利用

22. 3 Polysaccharide An alternative name for glycan ;
Any linear or branched polymer consisting of monosaccharide residues. Important polysaccharides include glycogen, starch and cellulose .
Polysaccharide【多糖】 glycan【聚糖】polymer 【多聚物】glycogen【糖原】, starch【淀粉】and cellulose【纤维素】.能水解成多个单糖分子，属于高分子碳水化合物，分子量可达到数百万。

23. Starch
Energy store of plants

24. Amylose It can be made of several thousand glucose units.
In amylose, the 1st carbon on one glucose molecule is linked to the 4th carbon on the next glucose molecule (α(1→4) bonds).
Amylose is soluble in water.
Amylose【直链淀粉】α(1→4)葡萄糖苷键
遇碘呈紫蓝色

25. Amylopectin
Amylopectin【支链淀粉】α(1→6)糖苷键
Glucose units are linked in a linear way with α(1→4) glycosidic bonds. Branching takes place with α(1→6) bonds occurring every 24 to 30 glucose units.
It is not soluble in water.

26. Glycogen
Glycogen is found mainly in the liver and skeletal muscle.
Muscle: energy (ATP) production. Liver: balance blood glucose levels.
Glycogen【糖原】skeletal muscle【骨骼肌】糖原是肝脏和骨骼肌中的贮能物质

27. Cellulose A linear, unbranched β l-4 glucan molecular

28. Lecture 3 Glycolysis
Chapter 11 Glycolysis

29. In glycolysis, a molecule of glucose is broken down in a series of enzyme-catalyzed reactions to yield two molecules of the three-carbon compound pyruvate . During the sequential reactions of glycolysis, some of the free energy released from glucose is conserved in the form of ATP and NADH.
葡萄糖(glucose)经过酶催化作用降解成丙酮酸，并伴随生成ATP和NADH的过程。

30. First stage of carbohydrate metabolism.
Glycolysis was first discovered by Gustav Embden and Otto Meyerhof and Parnus. Glycolysis is named as EMP
Simple sugars are broken down to pyruvate
No oxygen needed.
All life uses this process.
There are 10 steps in glycolysis.

31. 1 The Reaction of the glycolysis (Two Phases)
Preparatory phase（step①-⑤）：Phosphorylation of glucose and its conversion to glyceraldehyde 3-phosphate
Payoff phase（step⑥-⑩）：
Oxidative conversion of glyceraldehyde 3-phosphate to pyruvate and the coupled formation of ATP and NADH

32. (1) Phosphorylation of Glucose
or glucokinase
Phosphorylation of Glucose (葡萄糖磷酸化)
Glucose is phosphorylated by ATP to form glucose 6-phosphate and ADP. The reaction is catalyzed by the enzyme hexokinase (己糖激酶)or glucokinase【葡糖激酶】.消耗ATP,不可逆反应
Transfer of a phosphoryl group from ATP to glucose

33. (2) Isomerization :Conversion of Glucose 6-Phosphate to Fructose 6-Phosphate
Glucose 6-phosphorylated is converted to fructose 6-phosphate by phosphohexose isomerase[磷酸己糖异构酶]
6-磷酸葡萄糖 磷酸己糖异构酶 6-磷酸果糖

34. (3) Phosphorylation of Fructose 6-Phosphate to Fructose
1,6-Bisphosphate
Fructose 6-phosphate is phosphorylated by ATP to form fructose 1,6-bisphosphate and ADP. The reaction is catalyzed by the enzyme phosphofructokinase (PFK 磷酸果糖激酶).消耗ATP，不可逆反应

35. (4) Cleavage of Fructose 1,6-Bisphosphate
Aldolase(醛缩酶) splits fructose 1,6-biphosphate into two three-carbon molecules,glyceraldehyde3-phosphate and dihydroxyacetone phosphate
(醛缩酶

37. （5）Interconversion of the Triose Phosphates
磷酸丙糖的互变Glyceraldehyde 3-phosphate is the only molecule that can be used for the rest of glycolysis. However, the dihydroxyacetone phosphate can be converted to Glyceraldehyde 3-phosphate by triose phosphate isomerase. This is an equilibrium.

38. (6) Oxidation of Glyceraldehyde 3-Phosphate to
1,3-Bisphosphoglycerate
Glyceraldehyde 3-phosphate is converted to 1,3-bisphosphoglycerate. The reaction is catalyzed by glyceraldehyde 3-phosphate dehydrogenase and uses inorganic phosphate and NAD+. The other product is NADH.
Oxidation and phosphorylation, yielding a high-energy mixed-acid anhydride

39. (7) Phosphoryl Transfer from 1,3-bisphosphoglycerate to ADP
Phosphoglycerate kinase catalyzes the transfer of the phosphoryl group from the 1,3- bisphosphoglycerate to ADP, generating ATP and 3-phosphoglycerate.
Transfer of a high-energy phosphoryl group to ADP, yielding ATP

40. (8) Conversion of 3-Phosphoglycerate to 2-Phosphoglycerate
3-Phosphoglycerate is converted to 2-phosphoglycerate by phosphoglycerate mutase. Thus the reaction is a movement of the phosphate group to a different carbon atom within the same molecule.

41. (9) Dehydration to an energy-rich enol ester
PEP
烯醇化酶
Enolase catalyzes the dehydration of 2-phosphoglycerate to form phosphoenolpyruvate (PEP). This reaction convert low-energy phosphate ester bond of 2-phosphoglycerate into the high-energy phosphate bond of PEP.

42. (10) Transfer of the Phosphoryl Group from Phosphoenolpyruvate to ADP
Transfer of a high-energy phosphoryl group to ADP, yielding ATP

45. For each molecule of glucose that passes through the preparatory phase (a), two molecules of glyceraldehyde 3-phosphate are formed; both pass through the payoff phase (b), Pyruvate is the end product of the second phase of glycolysis.

46. For each glucose molecule, two ATP are consumed in the preparatory phase and four ATP are produced in the payoff phase, giving a net yield of two ATP per molecule of glucose converted to pyruvate.

47. The glycolytic breakdown of glucose is the sole source of metabolic energy in some mammalian tissues and cell types (erythrocytes, renal medulla, brain, and sperm, for example).
Many anaerobic microorganisms are entirely dependent on glycolysis.

48. ATP and NADH Formation Coupled to Glycolysis
During glycolysis some of the energy of the glucose molecule is conserved in ATP, while much remains in the product, pyruvate. The overall equation for glycolysis is

49. Regulation of glycolysis
Three glycolytic reactions(the reactions catalyzed by hexokinase, PFK-1, and pyruvate kinase) are irreversible.
1. Phosphofructokinase （PFK）
Inhibited by：ATP，Citrate
Activated by：AMP， 2,6-bisphosphate（F-2,6-BP）
. phosphofructokinase【磷酸果糖激酶】（PFK）
inhibited by：ATP，Citrate 【柠檬酸】
activated by：AMP，fructose 【果糖】
2,6-bisphosphate（F-2,6-BP）

50. 2 Hexokinase Inhibited by：G-6-P pyruvate kinase Inhibited by：ATP
Activated by：FBP
hexokinase【己糖激酶】pyruvate kinase【丙酮酸激酶】

52. Lecture 4 The fates of pyruvate
Anaerobic【无氧】

54. Three catabolic routes.
1. oxidized to acetyl-CoA
2. Ethanol fermentation
3. Lactic acid fermentation

55. Lactic acid fermentation
Under anaerobic conditions, reduction of pyruvate provides a means of reoxidizing the NADH produced in the glyceraldehyde-3-phosphate dehydrogenase reaction of glycolysis converted to lactate.
glyceraldehyde-3-phosphate dehydrogenase 【磷酸甘油醛脱氢酶】 在无氧条件下，把糖酵解中生成的NADH中的H交给丙酮酸生成乳酸的过程称为乳酸发酵。

56. Lactic acid fermentation

57. Ethanol fermentation
The reduction of acetaldehyde to ethanol by NADH, under anaerobic conditions
【乙醛】在无氧条件下，把糖酵解中生成的NADH中的H交给丙酮酸脱羧产物乙醛生成乙醇的过程称为乙醇发酵。

58. Ethanol fermentation

59. Aerobic pathways for pyruvate
The five coenzymes participating in this reaction: TPP, Lipoic Acid , CoA-SH, NAD+, FAD,
（氧化脱羧成CH3COCoA）

60. The Pyruvate Dehydrogenase Complex Consists of Three Distinct Enzymes
Pyruvate dehydrogenase (E1)
Dihydrolipoyl transacetylase (E2)
Dihydrolipoyl dehydrogenase(E3)
pyruvate dehydrogenase（丙酮酸脱氢酶）
dihydrolipoyl transacetylase（二氢硫辛酸转乙酰酶）
dihydrolipoyl dehydrogenase（二氢硫辛酸脱氢酶）
cofactors (Coenzymes) ：
TPP, Lipoic Acid(硫辛酸), CoA-SH, NAD+, FAD,

61. FIGURE 16–5 The pyruvate dehydrogenase complex.

62. FIGURE 16–6 Oxidative decarboxylation of pyruvate to acetyl-CoA by the PDH complex.