7/31/2019 1 Glycolysis

1/45

METABOLISM

7/31/2019 1 Glycolysis

2/45

Metabolism

Metabolism: is the sum ofall the chemical reactionsin the body.

7/31/2019 1 Glycolysis

3/45

Metabolism can be

Anabolism larger molecules are made from smaller ones

usually requires energy

reduction reactions

Catabolism

larger molecules are broken down into smaller ones

usually releases energy

oxidation reactions Amphibolism (amphi = both)

Some pathways serve both in catabolism and anabolism,such pathways are amphibolic

7/31/2019 1 Glycolysis

4/45

metabolism

catabolism

anabolism

Complex molecules

catabolism

anabolism

Simple molecules ATP [H]

Catabolism & Anabolism

7/31/2019 1 Glycolysis

5/45

CARBOHYDRATE

METABOLISM

7/31/2019 1 Glycolysis

6/45

Can you tell me :

Why do we need glucose in our body ?

7/31/2019 1 Glycolysis

7/45

Structure of : Adenosine Triphosphate

A P P P

7/31/2019 1 Glycolysis

8/45

Energy Production from Glucose

A P P P

Glucose is broken down intomany molecules of ATP(higher if O2 present)

A P P P+

C6H12O6

When bond is broken, energyis released

AdenosineDiphosphate

7/31/2019 1 Glycolysis

9/45

Glucose Cellular Uptake

Glucose transporters ( GLUT) GLUT 1 GLUT 2 GLUT 3 GLUT 4 in muscle and adipose tissue GLUT 5Insulin helps GLUT 4 to take glucoseinto cells.

7/31/2019 1 Glycolysis

10/45

GLYCOLYSIS

Glycys = sweetLysis = breakdown

7/31/2019 1 Glycolysis

11/45

Definition of Glycolysis

first pathway for thebreakdown of carbohydrates

7/31/2019 1 Glycolysis

12/45

General Properties of Glycolysis

Takes place in the cytosol ofALL cells

Can be aerobic or anaerobic

Takes place in ten reactions

7/31/2019 1 Glycolysis

13/45

Glycolysis can be divided into

two phases:

A) Energy-requiring phaseB) Energy-yielding phase

7/31/2019 1 Glycolysis

14/45

10 Steps of Glycolysis

7/31/2019 1 Glycolysis

15/45

A)The Energy-requiring Phase

These are five reactions.

Two ATPs are usedGlucose is broken down into

two glyceraldehyde-3-phosphate (G-3-P).

7/31/2019 1 Glycolysis

16/45

7/31/2019 1 Glycolysis

17/45

Hexokinase

Phosphohexose

isomerase

Phospho-Fructosekinase-1

Aldolase

Triose

phosphate

isomerase

7/31/2019 1 Glycolysis

18/45

Reaction 1: Phosphorylation of glucose

Irreversible reaction

7/31/2019 1 Glycolysis

19/45

Kinases: (transferases): catalyze the

transfer of a phosphoryl group fromATP to some molecule.

Liver cells also contain an isozyme ofhexokinase called glucokinase

Isozymes : Two enzymes that catalyzethe same reaction but differ in chemicaland physical properties

7/31/2019 1 Glycolysis

20/45

Hexokinase & Glucokinase

7/31/2019 1 Glycolysis

21/45

Hexokinase & Glucokinase

Hexokinase: Km 0.1 mM

So hexokinase is

normally active! Found in most cells

Works with all hexoses

Inhibited by G6P

Glucokinase: Km 10 mM

only works when glucose

concentration is high Found in liver, pancreas

Works ONLY with glucose

Not inhibited by G6P

7/31/2019 1 Glycolysis

22/45

Reaction 2: Isomerization of glucose 6-phosphate

7/31/2019 1 Glycolysis

23/45

glucose is an aldose, fructose is a ketose.

7/31/2019 1 Glycolysis

24/45

Reaction 3:Phosphorylation of fructose 6-phosphate

Irreversible reaction

The rate-limiting step in glycolysis

7/31/2019 1 Glycolysis

25/45

Reaction 4: Cleavage of fructose 1,6-bisphosphate

F 1,6-BP

DHAP

G 3-P

7/31/2019 1 Glycolysis

26/45

7/31/2019 1 Glycolysis

27/45

Reaction 5: isommerization of DHAP

7/31/2019 1 Glycolysis

28/45

7/31/2019 1 Glycolysis

29/45

B) The Energy-yielding Phase

These are five reactions.

4 ATP and 2NADH are produced.

Glyceraldehyde-3-phosphate isoxidized to pyruvate

Reaction 6: Glyceraldehyde 3 phosphate is oxidized

7/31/2019 1 Glycolysis

30/45

Reaction 6: Glyceraldehyde-3-phosphate is oxidized

Addition of a phosphate group to G3P

No ATP or ADP is involved

H transfer to NAD+ forming NADH

7/31/2019 1 Glycolysis

31/45

Substrate-level phosphorylation

7/31/2019 1 Glycolysis

32/45

Reaction 7: synthesis of ATP

7/31/2019 1 Glycolysis

33/45

Reaction 8: Conversion of 3-phosphoglycerate to 2phosphoglycerate

7/31/2019 1 Glycolysis

34/45

The phosphoglycerate mutase

reaction

3-phosphoglycerate2,3-bisphosphoglycerate2-phosphoglycerate

Phospho-

glycerate

mutase

COO-

|

HCOH|

CH2O

7/31/2019 1 Glycolysis

35/45

Reaction 9; removal of water from 2-phosphoglycerate

7/31/2019 1 Glycolysis

36/45

Reaction 10: synthesis of ATP

Irreversible reaction

7/31/2019 1 Glycolysis

37/45

7/31/2019 1 Glycolysis

38/45

End-productsof Glycolysis

C C C C C C

C CC C C

C C C

4 ATP

2 ATP

Glucose

2 G3P

2 ADP

4 ADP

2 Pyruvate

2 NAD+

2 NADH

P

C

P

7/31/2019 1 Glycolysis

39/45

ATPs produced from glycolysis

7/31/2019 1 Glycolysis

40/45

End-products of Glycolysis

Glucose Pyruvate

Net:2 ATP2 NADH2 P ruvate molecules

7/31/2019 1 Glycolysis

41/45

Glycolysis RegulationGlucose

Pyruvate

10 steps 3 regulated steps

3 reactions are irreversible

These can be regulated

7/31/2019 1 Glycolysis

42/45

Anaerobic Glycolysis

If O2 is absent, pyruvate cannot beoxidized further to give energy.

Pyruvate is reduced to lactic acidso that NAD+ will be still availablefor further glycolysis

7/31/2019 1 Glycolysis

43/45

Anaerobic Glycolysis

7/31/2019 1 Glycolysis

44/45

7/31/2019 1 Glycolysis

45/45

Wishing u a nice id holiday!