Ch22:CarbohydrateMetabolism

Chem30B

CatabolismOverview

Diges;onofCarbohydrates

VilliofSmallIntes;ne

[Handout]CatabolismFlowChart

CARBOHYDRATES

Glucose 6-phosphate

LIPIDS

5-C sugars + NAPDH

Pentose PhosphatePathway Glycogenesis

Glycogen

Glucose +Other Sugars

H3C C

O

C

O

O-

Pyruvate

Acetyl-CoAH3C C

O

SCoA

3 NADH, 1 FADH2

Electron TransportChain & Oxidative

Phosphorylation

11 ATP(3 ATP/NADH + 2 ATP/FADH2)

Citric AcidCycle

2 NADH + 2 ATP

NADH

1 ATP 2 CO2

*Glycolysis yields 2 pyruvates, so multiply everything below by 2x!

O2

H2O

Fatty Acids + Glycerols

Fatty Acids

β-oxidation

n NADH+ n FADH2

Steroids

Ketone bodies

PROTEINS

Amino Acids

Amino AcidCatabolism

Protein metabolism

CO2

FOOD

Glycolysis

LactateAnaerobic

Aerobic

(n depends on carbonlength of fatty acid)

[Handout]Glycolysis

H

OH

OHH OH

OH H

OHexokinase

Glucose Glucose 6-phosphate

Glucose 6-phosphateisomerase

CH2OH

OH

H

CH2

OH H

H OHO

2-O3PO ADPATP

Fructose 6-phosphate kinaseCH2HO

H

OH

OHH OH

OH H

OCH22-O3PO

Fructose 6-phophate

CH2OPO32-

OH

H

CH2

OH H

H OHO

2-O3PO

Fructose 1,6-bisphosphate

Aldolase

H2C C

OCH2OH2-O3PO

CH

CHOH2

COH

Dihydroxyacetone phosphate

D-Glyceraldehyde3-phosphate

Triose phosphateisomerase

Glyceraldehyde 3-phosphate dehydrogenase

NADH/H+

1,3-Bisphosphoglycerate

ADP ATPPhosphoglycerate kinase

3-Phosphoglycerate

Phosphoglycerate mutase

2-Phosphoglycerate

Enolase H2O

2-O3PO CH

CO

OPO32-H2C

OH2-O3PO

CH

CO

O–H2C

OH2-O3PO C

HCO

O–H2C

OPO32–

HO C CO

O–H2C

OPO32–

Phosphoenolpyruvate

C CO

O–H3C

Pyruvate kinaseO

Pyruvate

ADP ATP

ADPATP

1 2 3

45

6

7 8 9

10

NAD+ HOPO32-

GlucosetoAcetyl-CoA

[Handout]ATPAccoun;ngforGlucoseCatabolism

H.KimforChem30B

3

GlucoseandFattyAcidCatabolism

I.GlucoseCatabolism A.StepsofGlucoseCatabolism1.Glycolysis:glucose+2NAD++2HOPO32-+2ADPà2pyruvate+2NADH+2ATP+2H2O+2H+

2.PyruvateOxidation:2pyruvate+2NAD++2HSCoAà2Acetyl-CoA+2CO2+2NADH+2H+3.CitricAcidCycle:2Acetyl-CoA+6NAD++2FAD+2ADP+2HOPO32-+4H2Oà2HSCoA+6NADH+6H++2FADH2+ 2ATP+4CO2 4.ElectronTransport/OxidativePhosphorylation:ElectronsfromalltheNADHandFADH2madeinthepreviousstepsareusedtoreduceO2towater: O2+4e-+4H+à2H2OThereleasedenergyisusedtomakeATP: 3ATPmade/1NADH 2ATPmade/1FADH2

(Moreaccurate:2.5ATP/NADH,1.5ATP/FADH2)

B.TotalATPCountforCatabolismofaGlucoseMolecule

• Glycolysis:2ATP+6ATP(from2NADH)=8ATP• Pyruvateoxidation:6ATP(from2NADH)=6ATP• CitricAcidCycle:2ATP+18ATP(from6NADH)+4ATP(from2FADH2)=24ATP

_________________________________________________________________________________________________________ TOTAL:38ATP