GLYCOLYSIS

1
GLYCOLYSIS
CITRIC ACID CYCLE
2
PRIMARY METABOLISM
hn
Photosynthesis
Glucose
SECONDARY METABOLISM
GLYCOLYS IS
We will now investigate the important
glycolysis pathway.
The end product of the glycolysis pathway
is acetyl coenzyme A an important
two-carbon intermediate for the synthesis of the
secondary metabolites known as acetogenins,
terpenes and steroids.
Fatty Acids Lipids
Acetyl CoA
Acetogenins Terpenes Steroids
Citric Acid Cycle
CO2 H2O ATP
3
CONVERSION OF GLUCOSE TO FRUCTOSE
ATP
ADP
H
B
H
hemiacetal
B
glucose-6-phosphate
enolization
B
ketolization
H
..
ene-diol
H
fructose-6-phosphate
B
4
ADENOSINE TRIPHOSPHATE (ATP)
1) modifies alcohols for greater reactivity
ATP
Modifies alcohols to phosphates or diphosphates.
ADP
Nu
Nu-R

P
AMP
SN1 or SN2
good leaving group
5
ADENOSINE TRIPHOSPHATE (ATP)
2) traps alcohols and sugars to drive transport
across cell walls
X
low CONC
High CONC
fast
CELL WALL
3) transfers energy in coupled reactions
ATP
gains energy
ADP
loses energy
6
CLEAVAGE OF FRUCTOSE ( C6 2 x C3 )
H
ATP
ADP
fructose-1,6-diphosphate
fructose-6-phosphate
1,3-dihydroxyacetone phosphate
3-phosphoglyceraldehyde
B
H
The two fragments are essentially the same
as they can interconvert via the enediol.
enediol
7
CONVERSION TO PHOSPHOENOLPYRUVATE (PEP)
3-phosphoglyceraldehyde
..

..

..
-


NAD
ADP
H
oxidative phosphoylation
ATP
H
B
- H2O
..
B
intramolecular shift of phosphate
phosphoenolpyruvate
8
OXIDATIVE PHOSPHORYLATION
ELECTRON TRANSPORT CHAIN
Pi ADP
ATP
Pi ADP
ATP
2e
2e
2 H2O
2 Fe3
FAD
NADPH
REDUCED COENZYME Q
cytochrome systems
OXIDIZED COENZYME Q
NADP
FADH2
O24H
2 Fe2
2e
2e

3 ATP produced per oxygen
this pair of electrons is eventually transferred
to oxygen to make water
NADPHs and FADH2s are accumulated from
glycolysis and the citric acid cycle
36 ATPs from glucose 2 formed directly in
glycolysis
9
ELECTRON TRANSPORT CHAIN
2e-
NADPH H2O DG -52.6 kcal/mole
ADP Pi ATP DG 7.3 kcal/mole
NADP
2 ATP
FAD
Decreasing Energy
Coenzyme Q
The electrons captured in each oxidation are
passed from one carrier to another, each lower in
energy, until they end up transferred to oxygen
to make water.
Cytochromes
2 ATP
O2 2 H2O
The lost energy is saved in ATP molecules.
42 conversion !
10
CONVERSION TO ACETYL COENZYME A
H
ADP
ATP
pyruvic acid
..

..
phosphoenolpyruvate
We already showed this process when we discussed
tropic acid biosynthesis - the earlier slide
is repeated on the next slide.
Thiamine Lipoic acid Coenzyme A
acetylCoA
AcetylCoA is an extremely important
intermediate that is fed into the citric acid
cycle for energy production and is also used as a
two-carbon building block for synthesis
11
HOW THIAMINE, LIPOIC ACID AND CoA WORK TOGETHER
DECARBOXYLATION AND OXIDATION OF AN a-KETOACID
..


- CO2
TPP
-
..
Enz-BH
pyruvic acid
Lip(S)2
Enz-B
HB-Enz
acetylCoA


-
..
CoASH
..

12
CITRIC ACID CYCLE
13
PEP
Biotin-COOH
Acetyl CoA
Biotin
CoASH
Citrate
Oxaloacetate
- H2O
NADPH
cis -Aconitate
NADP
ATPs
CITRIC ACID CYCLE
Malate
H2O
ATPs
H2O
ATPs
NADPH
NADP
FAD
TPP LIPS2 CoASH
Isocitrate
FADH2
Fumarate
- CO2
a-Ketoglutarate
- CO2
Succinate
14
SELECTED REACTIONS
enol acetyl CoA
B
..

H
aldol condensation
oxaloacetic acid
hydrolysis
(oxaloacetate)
citric acid
(citrate)
B
- H2O
continued
H
H2O
isocitric acid
(isocitrate)
15
NADP
NADPH
B
isocitric acid
(isocitrate)
NADP
H
- CO2
a-ketoglutaric acid
H
B
continued
16

a-ketoglutaric acid
TPP
B

H
LIPS2

B
H
S-CoA
..
succinic acid
17
FAD
FADH2
fumaric acid
succinic acid
H2O
NADP
NADPH
oxaloacetic acid
BACK AGAIN TO THE BEGINNING
18
OVERVIEW
19
Glucose (6 carbons)
photosynthesis
starch
n
glycolysis
erythrose- 4-phosphate
phosphoenol pyruvate (PEP) (3 carbons)
shikimic acid
anthanilic acid
acetyl- coenzymeA (2 carbons)
mevalonic acid
oxalo- acetate
lysine ornithine
phenylalanine tyrosine
energy (ATP) CO2 H2O
tryptophan
terpenes steroids carotenoids
NH3
nicotinic acid
aspartic acid
glutamic acid