Download Glycolysis

Glycolysis
Biochemistry, 4th edition, RH Garrett & CM Grisham,
Brooks/Cole (Cengage); Boston, MA: 2010
pp 535-562
Instructor: Kirill Popov
1. General metabolism of glucose
2. The reactions of glycolysis
3. Metabolism of hexoses other than glucose
4. Control of metabolic flux
Fate of major metabolic fuels
Glycogen
Triglyceride
Protein
Glycogenolysis Lipolysis
Glucose
Free fatty acids
Glycolysis
Proteolysis
Amino acids
β-Oxidation
Pyruvate
Oxidation
Acetyl-CoA
Deamination and
oxidation
Major metabolic pathways of glucose
Glycogen
storage
Glucose
oxidation via
pentose phosphate
pathway
Ribose 5-phosphate
oxidation via
glycolysis
Pyruvate
Catabolic fates of the pyruvate formed in glycolysis
Glucose
glycolysis
(10 successive
reactions)
anaerobics
conditions
2 Ethanol + 2 CO2
Fermentation to alcohol
in yeast
2 Pyruvate
anaerobics
conditions
anaerobics
conditions
2 Lactate
2CO2
2 Acetyl-CoA
citric
acid
cycle
4 CO2 + 4 H2O
Animal, plant, and
many microbial cells
under aerobic conditions
Fermentation to
lactate in vigorously
contracting muscle,
erythrocytes, some
other cells, and in
some microorganisms
Glycolysis is a preparatory pathway for aerobic
metabolism of glucose
glycolysis
D-Glucose
PDH
2 pyruvate
2 L-lactate
No O2 requirement
for glycolysis
2 acetyl-CoA
2CO2
TCA
4CO2
O2 requirement for pyruvate
dehydrogenase (PDH) plus
TCA cycle activity
Mechanism of glucose uptake
Glucose
Glucose
transporter
Jglucose (mM cm s-1 106)
Plasma
membrane
[Glucose] mM
Major ways in which glucose is metabolized in different tissues
Glucose
Glucose
Pentose
phosphates
Pentose
phosphates
Glucose 6-phosphate
Glucose 6-phosphate
(2)Lactate-
(2)Lactate(2) H+
(2) CO2
e-
2 Acetyl-CoA
(2) H+
e-
TCA
(2) CO2
erythrocytes
brain
Glucose
Pentose
phosphates
?
Glucose
Pentose
phosphates
Glucose 6-P
Glycogen
Glucose 6-P
Glycogen
Glucurinides
(2)Pyruvate(2)Lactate(2) CO2
(2) H+
2 Acetyl-CoA
Glucose
(2)Pyruvate(2)Lactate(2) CO2
(2) H+
2 Acetyl-CoA
e-
TCA
TCA
Fat
(2) CO2
muscle
liver
(2) CO2
e-
first
priming
reaction
Glucose
ATP
1
ADP
HO
Preparatory phase
CH2
O
Phosphorylation of glucose
and its conversion to
glyceraldehyde 3-phosphate
OH
OH
OH
OH
Glucose 6-phosphate
P
O
CH2
O
OH
2
OH
OH
OH
Fructose 6-phosphate
second
priming
reaction
cleavage
of 6-carbon
sugar
phosphate to
two 3-carbon
sugar
phosphates
3
P
O
CH2
CH2 OH
O
ATP
ADP
Fructose 1,6-bisphosphate
1
Hexokinase
2
Phosphohexose
isomerase
OH
OH
P O
CH2
CH2 O
O
P
Phosphofructokinase-1
Aldolase
3
OH
4
OH
4
Triose
phosphate
isomerase
5
O
P
Glyceraldehyde 3-phosphate
O
CH2
CH
C
H
OH
Dihydroxyacetone phosphate
O
P
CH2
C CH2 OH
O
5
oxidation and
phosphorylation
first ATPforming reaction
(substrate-level
phosphorylation)
Glyceraldehyde 3-phosphate (2)
2Pi
2NAD+
6
2 NADH + H+
1,3-Bisphosphoglycerate (2)
7
O
P
CH2
CH
OH
CH2
CH
Oxidative conversion of
glyceraldehyde 3-phosphate to
pyruvate and the coupled
formation of ATP and NADH
O
OH
2 ATP
P
O
P
O
CH2
CH
8
C
O-
6
Glyceraldehyde 3-phosphate
dehydrogenase
O-
7
Phosphoglycerate
kinase
O
8
Phosphoglycerate
mutase
O
2-Phosphoglycerate (2)
CH2
CH
OH
O
C
P
9
CH2
Pyruvate (2)
C
O-
P
2ADP
2 ATP
C
O
Phosphoenol pyruvate (2)
10
H
C
OH
second ATPforming reaction
(substrate-level
phosphorylation)
Payoff phase
O
O
P
2ADP
3-Phosphoglycerate (2)
O
C
CH3
C
O
O
C
O-
9
10
Enolase
Pyruvate
kinase
Phosphorylation of glucose
O
HO
6
CH2
O
ATP
ADP
Mg2+
OH
OH
OH
OH
hexokinase
-O
P
O
CH2
O
O-
5
4
OH
1
OH
OH
3
2
OH
Glucose
Glucose 6-phosphate
ΔG'º = -16.7 kJ/mol
Conversion of glucose 6-phosphate to fructose 6-phosphate
O
O
6
-O
P
O
-
O
CH2
5
4
-
O
O
1
OH
Mg2+
OH phosphohexose
OH
3
1
6
2
OH
Glucose 6-phosphate
isomerase
P
CH2
O
-
O
O
5
4
CH2 OH
OH
2
3
OH
Fructose 6-phosphate
ΔG'º = 1.7 kJ/mol
Phosphorylation of fructose 6-phosphate to fructose
1,6-bisphosphate
O
-
O
P
O-
6
CH2
O
O
1
O
5
4
OH
CH2 OH
OH 2
3
Fructose 6-phosphate
ATP
ADP
Mg2+
phosphofructokinase-1
-O
P
O-
O
6
1
CH2
CH2 O
O
5
4
OH
OH 2
O
P
O-
3
Fructose 1,6-bisphosphate
ΔG'º = -14.2 kJ/mol
O-
Cleavage of fructose 1,6-bisphosphate
O
-O
P
O-
O
6
1
CH2
CH2 O
O
5
4
OH 2
3
OH
Fructose 1,6-bisphosphate
P
O-
O
O
O
-
O
CH2
aldolase
C
O
O
C
O-
P
H
+
-
O
HCOH
CH2
CH2OH
O
O
P
O-
O-
Dihydroxyacetone
phosphate
Glyceraldehyde
3-phosphate
ΔG'º = 23.8 kJ/mol
Interconversion of the triose phosphates
O
CH2OH
C O
CH2
H
C
O
O P O
ODihydroxyacetone
phosphate
H COH
triose phosphate
isomerase
CH2
O
O
P
O-
OGlyceraldehyde
3-phosphate
ΔG'º = 7.5 kJ/mol
Oxidation of glyceraldehyde 3-phosphate to
1,3 bisphosphoglycerate
O
O
H
C
C
-
2-
Glyceraldehyde
3-phosphate
-
O
Inorganic
phosphate
O P O
NADH + H+ O
HO P O
HCOH
CH2OPO3
NAD+
O
glyceraldehyde
3-phosphate
dehydrogenase
O-
COH
CH2OPO321,3-Bisphosphoglycerate
ΔG'º = 6.3 kJ/mol
The glyceraldehyde 3-phosphate dehydrogenase reaction
CH2OPO32H C OH
CH2OPO3
C O
O
2-
-
O
H C OH
-
H C O
O P OH
O
O
Glyceraldehyde
3-phosphate
CH2OPO3
1
H C OH
2-
CH2OPO3
H+
2
S
NAD+
CH2OPO3
NADH + H+
3
H C OH
H C OH
NAD+
2-
H C OH
C O
C O
NAD+
S
NADH
Cys
Cys
Thiohemiacetal
Thioester
S
Cys
NAD+
SH
Cys
Glyceraldehyde 3-phosphate
dehydrogenase
O P O-
2-
1,3-Bisphosphoglycerate
4
Phosphoryl transfer from 1,3-bisphosphoglycerate to ADP
-
O
O
P
-
O P O
O
C
+
-
O
COH
CH2OPO3
2-
Mg2+
P
O
Rib
Adenine
-
O P O
O-
O
C
phosphoglycerate
kinase
+
COH
CH2OPO3
2-
P
P
O
Rib
1,3-Bisphosphoglycerate
ADP
3-Phosphoglycerate
ΔG'º = -18.5 kJ/mol
Adenine
ATP
Conversion of 3-phosphoglycerate to 2-phosphoglycerate
O-
O
C
HC
Mg2+
OH
CH2
-
O
O
O
O P O
-
O
3-Phosphoglycerate
phosphoglycerate
mutase
C
HC
O
-
O P O
-
CH2 OH O
2-Phosphoglycerate
ΔG'º = 4.4 kJ/mol
Mechanism of the phosphoglycerate mutase reaction
Enzyme with
unphosphorylated
His residue
His
2,3-Bisphosphoglycerate
initial
phosphorylation
of enzyme
ADP
kinase
3-Phosphoglycerate
-
O
-
O P O
His
3-Phosphoglycerate
Phosphoenzyme
2-Phosphoglycerate
phosphoglycerate
mutase
1
2,3-Bisphosphoglycerate
His
2
ATP
3-Phosphoglycerate
Dehydration of 2-phosphoglycerate to phosphoenolpyruvate
O-
O
C
O
H 2O
C
H C O P O
HO CH2
-
O
2-Phosphoglycerate
O-
O
enolase
O
C O P O
CH2
O-
Phosphoenolpyruvate
ΔG'º = 7.5 kJ/mol
Transfer of the phosphoryl group from
phosphoenolpyruvate to ADP
O-
O
C
O
C O P O +
CH2
-
O
P
-
O
C
P
Mg2+, K+
O
pyruvate
kinase
Rib
O-
O
-
O P O
C O +
P
CH3
P
Adenine
O
Phosphoenolpyruvate
ADP
Pyruvate
Rib
Adenine
ATP
ΔG'º = -31.4 kJ/mol
Pyruvate is the terminal electron acceptor in
lactic acid fermentation
Glucose
2 NAD+
2 NADH
2 Pyruvate
2 Lactate
Lactate dehydrogenase reaction
O-
O
C
C O
Pyruvate
CH3
NADH + H+
lactate
dehydrogenase
NAD+
O-
O
C
HO C H
Lactate
CH3
ΔG'º = -25.1 kJ/mol
Entry of dietary hexoses into the preparatory stage of glycolysis
CH2OH
Lactose
Trehalose
trehalase
O
OH
lactase
OH
OH
CH2OH
Pi
OH
OH
OH
Sucrose
OH
sucrase
D-Glucose
hexokinase
CH2OH
O
CH2OH
D-Galactose
phosphorylase
UDP-galactose
Glucose
UDP-glucose
1-phosphate
ATP
phosphoglucomutase
OH
Glucose
6-phosphate
OH
CH2OH
O
OH
ATP
Fructose
6-phosphate
Glyceraldehyde + Dihydroxyacetone
phosphate
triose
kinase
hexokinase
Mannose 6-phosphate
Phosphomannose
isomerase
Fructose 1-phosphate
fructose 1phosphate
aldolase
Fructose 1,6bisphosphate
triose phosphate
isomerase
Glyceraldehyde
3-phosphate
OH
D-Mannose
ATP
hexokinase
fructokinase
OH
OH
ATP
D-Fructose
ATP
OH
Glycogen; starch
O
The 2,3bisphosphoglycerate shunt
½ Glucose
1,3-Bisphosphoglycerate
ATP
2,3-Bisphosphoglycerate
ADP
3-Phosphoglycerate
2-Phosphoglycerate
Lactate
Insulin stimulates glucose uptake by adipose tissue and muscle
Glucose
Glucose
transporter
Endocytosis
Exocytosis
Stimulation
by insulin
Membranous
vesicle
Plasma
membrane
Relative enzyme activity
Kinetic properties of glucokinase and hexokinase
1.0
0
5 10 15 20
Glucose concentration (mM)
Regulation of glucokinase by sequestration in the nucleus
Capillary
Cytosol
GLUT2
Nucleus
Glucose
Glucose
Plasma
membrain
Hexokinase IV
Glucose 6-phosphate
Fructose 6-phosphate
Hexokinase IV
Regulator
protein
Regulation of phosphofructokinase-1
ATP
AMP, ADP
Fructose 6- + ATP
phosphate
citrate
Fructose 1,6- + ADP
phosphate
fructose 2,6bisphosphate
Relative Changes in [ATP] and [AMP] When ATP Is Consumed
Concentration
before ATP
depletion (mM)
Concentration after
ATP depletion (mM)
Relative change
ATP
5.0
4.5
10%
ADP
1.0
1.0
0
AMP
0.1
0.6
600%
Adenine
nucleotide
Regulation of phosphofructokinase-1
PFK-1 activity
Low [ATP]
High [ATP]
Fructose 6-phosphate
O
-
O
6
P
O
O
O C H2
-
O
O
5
H
2
OH
4
OH
HO
1
O
P
O
-
-
CH 2 OH
3
H
Fructose 2,6-bisphosphate
Role of fructose 2,6-bisphosphate in regulation of PFK-1
PFK-1 activity (% of Vmax)
100
80
+F2,6BP
60
40
-F2,6BP
20
0
0 0.05 0.1
0.2
0.4 0.7
1.0
[Fructose 6-phosphate] (mM)
2.0
4.0
Regulation of pyruvate kinase
Liver only
All glycolytic tissues, including liver
glucagon
F16BP
ATP
ADP
6 steps
PKA
PEP
ADP
P
Pyruvate
kinase L
(inactive)
Pyruvate
kinase
L/M
PP
H2O
ATP,
acetyl-CoA,
long-chain
fatty acids
ATP
Pyruvate
transamination
Pi
Alanine
Important regulatory features of glycolytic pathway
Glucose
ATP
−
ADP
Pentose
phosphate pathway
Glucose 6-phosphate
Glycogen
synthesis
Fructose 6-phosphate
AMP, Fructose 2,6-P2
ATP
+
ATP, citrate, H+
+
ADP
Fructose 1,6-bisphosphate
(2) Glyceraldehyde 3-phosphate
(2) NAD+ (2) Pi
(2) NADH + 2H+
(2) 1,3-Bisphosphoglycerate
(2) Phosphoenolpyruvate
(2) ADP +
+
(2) ATP
(2) Pyruvate
(2) NADH + 2H+
(2) NAD+
(2) Lactate
ATP, alanine
1.
Glycolysis is a near universal pathway by which a glucose molecule is oxidized
to two molecules of pyruvate, with energy conserved as ATP and NADH
2.
All ten glycolytic enzymes are in cytosol, and all the intermediates are
phosphorylated compounds of three or six carbons
3.
In the preparatory phase of glycolysis, ATP is invested to convert glucose to
fructose 1,6-bisphosphate; fructose 1,6-bisphosphate is than broken to yield
two molecules of triose phosphate
4.
In the payoff phase, each of the two molecules of glyceraldehyde 3phosphate undergoes oxidation; the energy of this oxidation is conserved in
the formation of NADH and ATP
5.
Glycolysis is tightly regulated in coordination with other energy-yielding
pathways