Molecular Biology of the Cell by Bruce Alberts, Alexander Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter by by Bruce Alberts, Alexander Johnson, Julian Lewis, David Morg

104 PANEL 2–8: Details of the 10 Steps of Glycolysis
For each step, the part of the molecule that undergoes a change is shadowed in blue,
and the name of the enzyme that catalyzes the reaction is in a yellow box.
Step 1 Glucose is
phosphorylated by ATP to
form a sugar phosphate.
The negative charge of the
phosphate prevents passage
of the sugar
phosphate through the
plasma membrane,
trapping glucose inside
the cell.
HO
CH 2 OH
O
OH
OH
glucose
OH
CH 2 O P
hexokinase
O
+ ATP
+ ADP +
HO
OH
OH
OH
glucose 6-phosphate
H +
Step 2 A readily
reversible
rearrangement of
the chemical
structure
(isomerization) 4
moves the
carbonyl oxygen HO
from carbon 1 to
carbon 2, forming a
ketose from an
aldose sugar.
(See Panel 2–3,
pp. 70–71.)
O H
6 CH 2 O
5
P
O
H
C1
C
2
OH
1 HO C H
OH
3
3 2 OH H C OH
4
OH
H C
5
OH
(ring form)
CH
6 2 O P
(open-chain form)
glucose 6-phosphate
1CH 2 OH
phosphoglucose C O
2
isomerase P OH 2 C CH 2 OH
HO C H
6 O
1
3
5 HO 2
H C OH
4
OH
4 3
H C OH
OH
5
CH
(ring form)
6 2 O P
(open-chain form)
fructose 6-phosphate
Step 3 The new hydroxyl
group on carbon 1 is
P
phosphorylated by ATP, in
preparation for the formation
of two three-carbon sugar
phosphates. The entry of sugars
into glycolysis is controlled at
this step, through regulation
of the enzyme
phosphofructokinase.
OH 2 C O CH 2 OH
phosphofructokinase
P OH 2 C O CH 2 O P
HO + ATP
HO + ADP + H +
OH
OH
OH
OH
fructose 6-phosphate
fructose 1,6-bisphosphate
Step 4 The
six-carbon sugar is
cleaved to produce
two three-carbon
molecules. Only the
glyceraldehyde
3-phosphate can
proceed immediately
through glycolysis.
P
OH 2 C O CH 2 O
HO
OH
OH
(ring form)
P
HO
H
H
CH 2 O P
C O
C H
C OH
C OH
CH 2 O P
aldolase
HO
CH 2 O
C
C
H
O
H
P
+
H
H
C
C
O
CH 2 O
OH
P
(open-chain form)
fructose 1,6-bisphosphate
dihydroxyacetone
phosphate
glyceraldehyde
3-phosphate
Step 5 The other
product of step 4,
dihydroxyacetone
phosphate, is
isomerized to form
glyceraldehyde
3-phosphate.
CH 2 OH
C
O
CH 2 O
P
dihydroxyacetone
phosphate
triose phosphate isomerase
H
H
C
C
O
OH
CH 2 O P
glyceraldehyde
3-phosphate