Chem30B
Ch22:CarbohydrateMetabolism
Catabolism
Overview
Diges;onofCarbohydrates
VilliofSmallIntes;ne
[Handout]CatabolismFlowChart
FOOD
LIPIDS
Glucose +
Other Sugars
Fatty Acids + Glycerols
Fatty Acids
5-C sugars
+ NAPDH
PROTEINS
CARBOHYDRATES
Pentose
Phosphate
Pathway
Amino Acids
Glycogenesis
Glucose 6-phosphate
β-oxidation
Glycogen
Glycolysis
2 NADH + 2 ATP
*Glycolysis yields 2 pyruvates,
so multiply everything below by 2x!
H 3C
O
O
C
C O-
Anaerobic
Aerobic
Pyruvate
n NADH
+ n FADH 2
NADH
CO2
(n depends on carbon
length of fatty acid)
Steroids
Ketone
bodies
Lactate
O
H 3C C
SCoA
Acetyl-CoA
Protein
metabolism
Amino Acid
Catabolism
[Handout]Glycolysis
Hexokinase
HO CH2
O OH
ATP
2-O
3PO
CH2
H
OH
OH
H
Glucose
3PO
O
H
4
CH2OPO32OH
Triose phosphate
isomerase
5
Glyceraldehyde 3-phosphate
dehydrogenase
OH O
H2
2-O PO C
C CH
3
H
NAD+ NADH/H+ HOPO32-
D-Glyceraldehyde
3-phosphate
7
OH O
H2
2-O PO C
C
3
H
C O–
3-Phosphoglycerate
Pyruvate kinase
ATP
ADP
10
O O
H 3C C C O –
Pyruvate
Phosphoglycerate mutase
8
2-O
H2
HO C
OPO32–
O
C C O–
H
2-Phosphoglycerate
OH O
H2
C C OPO323PO C
H
1,3-Bisphosphoglycerate
6
Phosphoglycerate kinase
ATP
H
Fructose 6-phophate
H
Fructose 1,6-bisphosphate
ADP
3
O
H2
PO
C C CH2OH
3
Aldolase
OH
H
CH2OH
OH
ADP
Dihydroxyacetone phosphate
OH
CH2
ATP
OH
H
Glucose 6-phosphate
2-O
2-O
2
OH
H
OH
O
H
H
OH
Fructose 6-phosphate kinase
Glucose 6-phosphate
2-O PO CH
isomerase
2
3
H
OH
1
H
OH
O OH
ADP
Enolase
9
H2O
H 2C
OPO32–
O
C C O–
Phosphoenolpyruvate
GlucosetoAcetyl-CoA
I.GlucoseCatabolism
A.StepsofGlucoseCatabolism
1.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+à2H2O
ThereleasedenergyisusedtomakeATP:
3ATPmade/1NADH
2ATPmade/1FADH2
(Moreaccurate:2.5ATP/NADH,1.5ATP/FADH2)
[Handout]ATPAccoun;ngforGlucoseCatabolism
B.TotalATPCountforCatabolismofaGlucoseMolecule
• Glycolysis:2ATP+6ATP(from2NADH)=8ATP
• Pyruvateoxidation:6ATP(from2NADH)=6ATP
• CitricAcidCycle:2ATP+18ATP(from6NADH)+4ATP(from2FADH2)=24ATP
_________________________________________________________________________________________________________
TOTAL:38ATP