Aulani "Biokimia" Presentation 3 Carbohydrate Metabolism Carbohydrate Metabolism Aulanni’am...

Aulani "Biokimia" Presentation 3Aulani "Biokimia" Presentation 3

Carbohydrate MetabolismCarbohydrate Metabolism

Aulanni’amAulanni’amBiochemistry LaboratoryBiochemistry LaboratoryChemistry DepartementChemistry Departement

Brawijaya UniversityBrawijaya University


CarbohydratesCarbohydrates

Carbohydrates are the most abundant organic Carbohydrates are the most abundant organic molecules in naturemolecules in nature Photosynthesis energy stored in carbohydrates;Photosynthesis energy stored in carbohydrates; Carbohydrates are the metabolic precursors of Carbohydrates are the metabolic precursors of

all other biomolecules;all other biomolecules; Important component of cell structures;Important component of cell structures; Important function in cell-cell recognition;Important function in cell-cell recognition; Carbohydrate chemistry:Carbohydrate chemistry:

Contains at least one asymmetric carbon Contains at least one asymmetric carbon center;center;

Favorable cyclic structures;Favorable cyclic structures; Able to form polymersAble to form polymers


Carbohydrate Nomenclature

Carbohydrate Classes:Carbohydrate Classes: Monosaccharides (CHMonosaccharides (CH22O)nO)n

Simple sugars, can not be broken down Simple sugars, can not be broken down further;further;

OligosaccharidesOligosaccharides Few simple sugars (2-6). Few simple sugars (2-6).

PolysaccharidesPolysaccharides Polymers of monosaccharidesPolymers of monosaccharides


Carbohydrate NomenclatureCarbohydrate Nomenclature

Monosaccharide (carbon numbers 3-7)Monosaccharide (carbon numbers 3-7) AldosesAldoses

Contain aldehydeContain aldehyde Name: aldo-#-oses (e.g., aldohexoses)Name: aldo-#-oses (e.g., aldohexoses)

Memorize all aldoses in Figure ?Memorize all aldoses in Figure ?

KetosesKetoses Contain ketonesContain ketones Name: keto-#-osesName: keto-#-oses ( (ketohexosesketohexoses))

CHO

OHH

OHH

OHH

OHH

CH2OH

1

2

3

4

56

CHO

OH

OHH

OHH

OHH

CH2OH

1

2

3

4

56


Monosaccharide Structures

O

a

e

a

a

a

a

e

e

a

e

a

e

a

e

a

e

a

Oeee

Axis Axis

Chair Boat

O

OH

H

OH

H

OH

OH

CH2OH

H

HH

O

H

HO

H

H

H

H

HO2HC

OHHOOH

-D-glucopyranose

Conformation of monosaccharide

Conformation of glucose


Disaccharides

Simplest oligosaccharides; Contain two monosaccharides linked by a

glycosidic bond; The free anomeric carbon is called reducing

end; The linkage carbon on the first sugar is

always C-1. So disaccharides can be named as sugar-(a,b)-1,#-sugar, where a or b depends on the anomeric structure of the first sugar. For example, Maltose is glucose-a-1,4-glucose. .


Structures of Disaccharides

Note the linkage and reducing endsNote the linkage and reducing ends

HOH

O

CH2OH

OH

OH

21

3

6

4

5O

CH2OH

OH

OH

OH

23

6

4

5

1O

Lactose (galactose--1,4-glucose)

HOH

O

CH2OH

OH

OH

21

3

6

4

5O

CH2OH

OH

OH

OH 23

6

4

5

1

Maltose (glucose--1,4-glucose)

O2

O

CH2OH

OH

OH

OH 23

6

4

5

1O CH2OH

CH2OH

OH

OHO

1

3 64

5

Sucrose (glucose--1,2-froctose) no reducing end

HOH

O

CH2OH

OH

OH

21

3

6

4

5O

CH2OH

OH

OH

OH 23

6

4

5

1O

Cellobiose (glucose--1,4-glucose)


PolysacchridesPolysacchrides Also called glycans;Also called glycans; Starch and glycogen are Starch and glycogen are storage storage molecules; molecules; Chitin and cellulose are Chitin and cellulose are structuralstructural molecules; molecules; Cell surface polysaccharides are Cell surface polysaccharides are recognitionrecognition molecules. molecules.

Glucose is the monosaccharides of the following polysacchrides with different linkages and banches

a(1,4), starch (more branch) a(1,4), glycogen (less branch) a(1,6), dextran (chromatography resins) b(1,4), cellulose (cell walls of all plants) b(1,4), Chitin similar to cellulose, but C2-OH is

replaced by –NHCOCH3 (found in exoskeletons of crustaceans, insects, spiders)


Overview of Glucose Overview of Glucose CatabolismCatabolism

Cells catabolize organic molecules and make ATP two ways: Substrate-Level Phosphorylation

Glycolysis Krebs (TCA) Cycle

Oxidative Phosphorylation Electron Transport Chain


Overview of Glucose CatabolismOverview of Glucose Catabolism


Overview of Glucose CatabolismOverview of Glucose Catabolism

Glycolysis Biochemical pathway

that produces ATP by substrate-level phosphorylation.

Yields a net of two ATP molecules for each molecule of glucose catabolized.

Every living creature is capable of carrying out glycolysis.

Most present-day organisms can extract considerably more energy from glucose through aerobic respiration.

C H O P A D P N A D

C H O A T P N A D H H

6 1 2 6 i

3 4 3

2 2 2

2 2 2

•Net reaction


Glucose primingGlucose priming


Cleavage and Cleavage and rearrangementrearrangement

P P


Krebs Cycle

After pyruvate has been oxidized, acetyl- CoA feeds into the Krebs cycle.

Krebs cycle is the next step of oxidative respiration and takes place in mitochondria. Occurs in three stages:

Acetyl-CoA binds a four-carbon molecule and produces a six-carbon molecule.

Two carbons are removed as CO2.

Four-carbon starting material is regenerated.

Cycle is also known as Tricarboxylic acid

(TCA) cycle Citric acid cycle

CH2

COOH

C

CH2

COOH

OH COOH

citric acid


Aerobic RespirationAerobic Respiration The pyruvic acid formed by glycolysis enters interior of The pyruvic acid formed by glycolysis enters interior of

mitochondria.mitochondria. Converted by coenzyme A to 2 molecules of acetyl CoA and 2 C0Converted by coenzyme A to 2 molecules of acetyl CoA and 2 C022.. Acetyl CoA serves as substrate for mitochondrial enzymes in the Acetyl CoA serves as substrate for mitochondrial enzymes in the

aerobic pathway.aerobic pathway.


CO2

CO2

CO2

NADHNADH

FADH

GTP

oxaloacetate (4C)

citrate (6C)

-ketoglutarate (5C)succinate (4C)

acetyl coenzyme A (2C)

pyruvate (3C)

NADH


Krebs CycleKrebs Cycle

Generates two ATP molecules per molecule of glucose.

Generates many energized electrons which can be directed to the electron transport chain to drive synthesis of more ATP: 6 NADH per molecule of glucose 2 FADH2 per molecule of glucose


Glycolysis


KREBS CYCLEKREBS CYCLE Takes place in Mitochondrion when oxygen is present Pyruvic acid from glycolysis is trimmed to a 2 carbon

compound Remaining carbon from glucose => CO2

Hydrogens transferred NAD+ => NADH FAD => FADH

Products of kreb cycle 3 NADHs 1 FADH2

2 ATP


The Cori Cycle

The reconversion of lactic acid to pyruvate sees the removal of fatiguing lactate from the site of production.

This forms the theoretical basis for the cool-down.

As the glycolysis pathway is reversible lactic acid can eventually be anabolised into glucose and stored in the liver, muscles or blood.


Electron Transport SystemElectron Transport System


EnergyEnergy CapacityCapacity to to performperform workwork..

Two examples:Two examples:

1.1. Kinetic energyKinetic energy

2.2. Potential energyPotential energy


Kinetic EnergyKinetic Energy EnergyEnergy in the process of doing work. in the process of doing work.

EnergyEnergy of of motionmotion..

Examples:Examples:

1.1. HeatHeat

2.2. Light energyLight energy

SUN


Potential Energy Energy that matter occupies because of it’s

location, arrangement, or position.

Energy of position.

Examples:1. Water behind a dam2. Chemical energy (gas)

GAS


Answer:Answer: adenosine triphosphate (ATP)adenosine triphosphate (ATP) Components:Components:

1.1. adenine:adenine: nitrogenous basenitrogenous base

2.2. ribose:ribose: five carbon sugarfive carbon sugar

3.3. phosphate group: chain of threephosphate group: chain of three

riboseribose

adenineadenine

P P P

phosphate groupphosphate group

Question:Question: What isWhat is ATP?ATP?


Answer:Answer: Works by the Works by the direct chemical transferdirect chemical transfer of a of a

phosphate groupphosphate group..

This is called This is called “phosphorylation”“phosphorylation”..

The The exergonic hydrolysisexergonic hydrolysis of of ATPATP is coupled with is coupled with the the endergonic processesendergonic processes by by transferringtransferring a a phosphate groupphosphate group to another molecule. to another molecule.


Hydrolysis of ATPHydrolysis of ATP

ATP + HATP + H22O O ADP + P (exergonic) ADP + P (exergonic)

HydrolysisHydrolysis(add water)(add water)

P P P

Adenosine triphosphate (ATPAdenosine triphosphate (ATP))

P P P++

Adenosine diphosphate (ADPAdenosine diphosphate (ADP))


Dehydration of ATPDehydration of ATP

ADP + P ADP + P ATP + H ATP + H22O (endergonic)O (endergonic)

Dehydration synthesisDehydration synthesis

(remove water(remove water))

P P P

Adenosine triphosphate (ATP)Adenosine triphosphate (ATP)

P P P++Adenosine diphosphate Adenosine diphosphate

(ADP(ADP))

Aulani "Biokimia" Presentation 3 Carbohydrate Metabolism Carbohydrate Metabolism Aulanni’am...

Documents

Transcript of Aulani "Biokimia" Presentation 3 Carbohydrate Metabolism Carbohydrate Metabolism Aulanni’am...