University of Groningen
The generation of metabolic energy in bacteria
Brink, Bart ten
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Publication date:
1984
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Citation for published version (APA):
Brink, B. T. (1984). The generation of metabolic energy in bacteria: the energy recycling model s.n.
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SUMMARY
creation
E.
in
ent
an outw
of
vesi<
coli
a membrane potential
The
role
in
bacterial
transl-ocation
medium,
as
electron
metabolism.
protons
of
result
a
transfer
bound ATPase.
trusion
in
generation
the
gradient
proton
chemical
parameter
in
synthesis
and
various
the
is
of
transport
of
the
rnembraneproton
ex(ApH)
a
regulatory
ATP
as moti-1ity,
the
across
seem to
only.
only
This
very
source.
of
bacteria
could
litt1e
is
mediated
soluÈes
the
membrane,
and/or
opposite
in
nÈg+
On the
other
direction
and
this
recycling"
tion
is
coli
what
ratio,
if
the
the
excretion
with
cell
solutes
across
since
then
systems
the
in
energy
translocation
of
course
in
of
solutes
postulation
the
of
the
of
in
intact
excretion
metabolic
excretion
experiments
of
energy
of
with
metabolic
nembrane
qlLgplgqgcque
-
and
requirement
the
endproducts
excreted.
AÈg+ generation
in
ce11s
of
are
106 -
Endproduct
therefore
of
the
a
endproduct
vesicles
_crsrnerrÊ.
that
also
can
v
between
In
conïn
lactate
of lt_gl_erlshl_q
The artificial
is
I
S
for
I
calculatec
decrr
t
(pl
Streptococcus
generated
produced
is
togethe
excreted
of
one
excretion
su
During
known.
tion
of
and 0.7
valents)
is
expe
concentrati
lactate)
excre-
bacteria.
coli
H+/lactat.e
cells.
the
of
is
E.
( Autac):
I
be depende
to
lactate
"energy-
model
"energy-recycling"
charges
metabolic
the
the
me
concentration;
The
in
the
force
be
can
car-
solute
generation
the
n
pears
this
of
of
cells
colyzing
gradient
occurs.
g+
stoichionetry
mem-
transport
with
concomittant
the
uplake
driving
adcti-
the
to
translocation
converted
energy
the
r
is
translocat
In
proton
postive
the
thesis
and
solved,
various
Led to
assumption
results
to
studied
breakdown of
supply
charge
hand,
results
is
and/or
then
tribute
this
is
carrier-mediated
protons
this
tate
model.
The basic
during
are
and varies
usually
gradl
it
course
that
q
of
lactate
rected
to
gen
A Èg +
cells
lactate
ATP hydrolysis
bacteria
these
many transport
proton-
present
by
membrane bound proteins,
also
gradients.
AÈn+,
of
across
transport
energy
in
used
during
would
by specific
The AÈH+ is
in
partly
be
could
electrontransfer
generation
since
produced
endproducts
possess
not
AÈg+
The transport
energy.
riers.
of
ATP is
problern
This
tional
able
do
be a problem,
metabolic
the
brane
be
which
lead
in
sults
magnitude
cytoplasmic
uncoup
results
cremoris
tion.
Anaerobic
by
growing
a
amino
efflux
of
membrane.
chains
S.
ZApH. The electroand
the
inhibited
tate
mernbrane-bound
a pH-gradient
such
solutes
by
of
take
external
by the
force
processes,
central
the
charqed,
both
<lriving
a
cel1ular
in
AÈn+ = Arl -
(Arl):
and a membrane potential
to
transport
positively
are
a
generated
cytoplasm
AtP hydrolysis
and/or
protons
plays
be
AÈH+ can
the
electron
chains
results
A
from
of
Since
(ngg+)
proton-gradient
electrochemical
rnolecu
(n-1)
of
ATP hydrolyzed,
valents
per
whereas
for
lac
lactate
n=1
no
higher
energy
gene
course
result
in
ê
creation
ent
of
q.__qg.]1 vesicles
in
plays
a
central
)e generated
sm to
.
the
in
is
by
take
the
external
tate
membrane-bound
by the
nembraneproton
charged,
a pH-gradient
ex(ApH)
S.
:h
as motility,
)ss
the
is
ATP
cytoplasmic
electrontransfer
. by
.kdown of
l,
if
growing
:he ceIl
tes
to
n
of
The
solute
in
generation
can
ic
of
a
is
rnodel is
that
is
also
tion
of
the
excre-
can
con-
bacteria.
endproduct
In
lactate
cles
of
ris.
The artificial
calculated
from
=
be dependent
Escherichia
n
on
produced
is
one
of
excretion
(n-1)
of
valents
whereas
per
n=1
the
a
no
generation
course
result
in
a
n
excrefrom
pH
The H+,/lacand g1y-
these
the
cel1s
close
zero'
to
the
lactate
Since
2
excretion
is
lactate
ce11
mM
ATP-equÍ-
anion
production
supply
will
yield.
' 1 0 7-
2
7 .0,
synthesized.
protons
sugar
cremoris
( in
therefore
gained
during
external
S.
(pH
1.8
energy
the
will
the
the
can be calcul-ated
per
will
in
have been calculated.
and 1 ATP is
-
in
increasing
metabolic
n protons,
hiqher
the
external
growing
very
between
lactate
energy
energy
the
in
lower
The energy gain
higher
on
pH 8.0).
is
excretion
protons.
lactate
lactate.
for
of
lactate
on ÀU , A pH and
fermentation
with
since
was determined
that
n t v ll a c t a t e )
lactate
molecule
ATP hydrolyzed,
in
internally
together
excreted
by
n
pH and/or
the
cremoris
by
di-
AUtac)/ AÈ H+.The value of n appH and the lactate
the external
both
results
sugar
determines
(at
and 2
stoichiometries
During
anion,
(n ) ,
dependent
data
the
(pH 5.5,50
generated
known.
in
protons
lactate
been deternined
( ^r],
decreasing
and 0.7
valents)
is
of
transl-ocation
(Atrtac)r
Streptococcus
In
n
value
pH 5.5)
lactate
H+/lactate
lactate)
endproducts
therefore
of
one
q_. c_Ëemo_liis.Assuming
concentration
ce11s.
the
has also
for
to
lactate
the
"energy-
Endproduct
.
between 1 (at
re-
outwardly
number of
production
energy
experiments:
cells
with
stoichiometry
vesicles
force
be
proton
1ing"
metabolic
concentration;
this
solutes
the
coli
in
that
shown
an
know the
to
toqether
H+/lactate
stoichiornetry
colyzing
important
very
always
1ac-
present.
is
the
uptake
pears
transport
the
In
car-
occurs.
ion of
tion.
mem-
ocation
re
of
E.
the
with
r of
maqnitude
the
rmittant
.n energy
ratio,
driving
a d < ]i -
is
indeed
that
excretion
is
it
up-
experiments
lactate
addition
cremolis
translocated
are
this
gradient
across
proteins,
ystems
energy
it
course
that
tate
excretion
with
lactate
rected
S.
Similar
of
the
completely
are
indicatinq
same conclusion:
gradient
the
processes
extrusion.
In
generation
and can drive
H+-ionophore),
generation.
of
cel1s
the
in
negative)
Both
gradi-
concentration
pH 6.6
at
proton
in
to
lead
A Èg +
and varies
usually
the
the
results
in
(a
uncoupler
cremoris
Iactate
ATP hydrolysis
se bacteria
by
lactate
proline.
acid
amino
efflux
Of
regulatory
a
the
sults
ZApH. The electrore and
of
inhibited
results
A9 (inside
a membrane potential
t+)
directed
an outwardly
by
if
in
lactate
was
the
per
ATP equin equals
excretion.
fermentation
This
Lactatê
excreted
(n-1)/2
be 50t
also
n
one
and excre-
result
are
if
2,
A
would
of
observed
in
continuous
cultures
of
S:_qr_ejnes_iji: at
pH 7.0
the
ce11 yielrl
was about 128 higher than at pH 5.7, which can be explained by
the effect
lactate
of
pH on n and therefore
excretion
In conclusion
strates
that
products
postulated
it
the
such as
can contribute
on the contribution
process to the energy qeneration.
to
can be said that
carrier-mediaterl
lactate
the
this
thesis
excretion
can result
in
model.
of
demon-
clearly
metabolic
bacteria,
the
De
AÈg+ generalion
energy requirenents
in the "energy-recycling"
of
of
endand
as was
electrochemis
belangrijke
kan
wordel
opgewekt
hei
naar
cytoplasma
transport
de
in
ro1
mernb
in
van A
hydrolyse
protonen
posit
tot
de vorming
van
een
mernbraanpotentÍ
zien
chemische
protongra
parameter
in
synthese
en
plasma
versch
het
tr
membraan.
groeier
Anaeroob
tronentransportkete
volledig
afhankelij
zou kunnen zi
bleem
ATP geprodur
weinig
giebron.
proble
Dit
a1s de uitscheiding
oplevert.
Het
geschiedt
met behul
de
In
carriers.
v
bruikt
om een bepa
teren;
aangezien
van
protonen
A!g+
wordt
gekeerd
dan
tot
" energy-recycl
Bij
bij
het
de
ducten
gr
en/of
leidt
tuurlijk
omg
tranl
de
v(
ing "
"energy-
carrier-gem
ook
protonet
den.
Eindproductuil
lÈn+
en
de
- 108 -
tranl
kan
bacterie.
een
In
b
d