acetyl-coa carboxylase in photosynthetic tissue - massey university
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ACETYL-CoA CARBOXYLASE IN PHOTOSYNTHETIC T I S SUE
A the s i s pre sented in parti al ful f i lment of the
requirements for the degree of Doctor of Philo sophy
in B iochemi stry at
MASSEY UNIVERS ITY
BASIL JOHN N IKOLAU
1 9 8 1
i i
ABSTRACT
Acetyl -CoA carboxylase catalyses the rate-limit ing reaction
in de novo f atty acid biosynthesis in a wide var iety of organisms. I n plants however , the signifi cance of this
enzyme in regulating de novo fatty ac id biosynthesis is
unknown.
In th is invest igat ion acetyl-CoA carboxylase of ma i z e , barley
and spinach leaves has been studied in order to compare some
features of this enzyme in the three pl ants . In mai ze ,
acetyl-CoA c arboxylase is located in chloroplasts , where i t occurs as a soluble enzyme in the stromal fraction . Both
mesophyll and bundle sheath ce l ls also exhibit acetyl -CoA
carboxylase activity . Activities of acetyl-CoA carboxylase
in isol ated c hloroplasts have been compared to rates of l ipid
synthesis from acetate in orde r to investigate the ro le o f acetyl-CoA carboxyl ase i n regul ating de novo fatty ac id bio
synthesis from acetate . Although acetyl -CoA carboxylase
activity was higher than that expected from the rate of
acetate incorporat ion into l ip ids of isolated chloroplasts o f mai ze and bar ley , the opposite was found for chloroplasts
isolated from spinach . In chloroplasts from the emerg ing
leaves of ma i ze seedl ings , l ipid synthesis was max imal with chloroplasts isolated from the leaf segment corresponding to
leaf greening . However , a relationship between leaf deve lop
ment and acetyl -CoA carboxylase activity was less apparent .
Consequently a regul atory role for acetyl-CoA carboxylase in de � fatty acid biosynthesis could not be d irectly estab
l ished from a compar ison of the rates of l ipid synthesis and
acetyl-CoA c arboxyl ase act iv i t ies .
An alternative approach to the establishment of a regulatory
role for acetyl -CoA carboxylase was to purify the enzyme
from mai ze and barley leaves , and study its response to var i
able concentrations o f substrates , products and certain
cellular metabolites . Pur i ficat ion of both enzymes was per-
lll
formed by identi c a l procedure s , includ ing polyethylene glycol
fract i onation , hydrophobic chromatography and ge l fi ltration .
Acetyl -CoA carboxylase from b?th mai z e and barley leave s
appeared to be an integral enzyme , a s no evidence for its
d i s sociation was found , contrary to the find i ngs of the
bacteri a l enzyme . The kinet ic properties o f the partially
puri fied enzyme from mai ze and bar ley were very similar . The
apparent Michael i s constants for the substrat e s , acetyl-CoA and HCO� , were about O . lmM and 2mM , respective ly for both
enzyme s . The enzymically active form of the substrate , ATP , was found to be Mg . ATP . Furthermore , free ATP inhibited
enzymic activity , while f ree Mg 2 + act ivated the enzyme from
both p l ant source s . Monovalent cations , particular ly K+,
were pos itive e f fectors o f acetyl-CoA carboxyl ase , on the
other hand , the products o f the acetyl -CoA c arboxylase re-
action , malonyl -CoA and ADP were inhibitor s . ADP inhibit ion
was compet itive with respect to ATP , but uncompetitive with
respect to acetyl-CoA . I nh ibition of acety l -CoA carboxylase
activ i ty by CoA was noncompet it ive with re spect to acetyl
CoA , while palmitoyl-CoA inhibition wa s uncompetit ive with
re spect to acetyl-CoA .
From the view point of regulation o f acetyl -CoA carboxylase
act iv i ty , the observed response o f activity to change s in pH ,
and the concentrat ions o f Mg2+, K
+ , ATP and ADP in vitro , may be o f s ign i f i c ance . Changes in the chloroplastic leve l s of
the se e f fecto r s of acety l-CoA carboxylase act ivity have been reported to occur during l ight-dark tran s i tion of chloro
plasts , and would be cons i stent in regulating acetyl -CoA carboxylase a c tivity in the light and dark .
iv
ACKNOWLEDGEMENTS
I wi sh to thank my superv i sor , Dr J C Hawke , for his invaluable advice , encouragement and a s s i s tance throughout the
cour se o f thi s study . I am a l so indebted to Dr C R S lack of
the Plant Physiology Divis ion , DSIR , for hi s advice and
a s s i stance , particularly dur ing the absence of Dr Hawke .
I would l ike to thank Mr I J Warr ington of the P l ant
Phys iology Divi s ion , DS I R , for helpful advice in the use o f
the c l imate control rooms for the growing o f mai ze and
barley plants .
In add it i on , particular thank s i s extended to Ms Joy Watson
for typi ng this manuscript .
ACP
ADP
AMP
ATP
BCCP
BSA
chl
P-CMB
CoA
DTT
EDTA
Hepe s
Mes
NADH
NADPH
NEM
PEG
PEP
2 -PGA
3 -PGA
LIST OF ABBREV IATIONS
acyl-carrier prote i n
adenos ine 5'-diphosphate
adenosine 5'-monophosphate
adenos ine 51-tr iphosphate
biotin carboxyl-carrier protein
bovine serum albumi n
chlorophy l l
P-chloromercuriben z oate
coenzyme A
d ithiothre itol
ethylenedi amine tetraace tic ac id
N-2-hydroxyethylpiperaz ine-N'- 2�ethane sulphonic
ac id
2[ N-Morphol i no] ethane sulphonic ac id
V
8-nicotinamide adenine dinucleotide , reduced form
n icotinamide adenine dinuc leotide pho sphate , re
duced form
N -ethylmale imide
pol�t hylene glycol
phosphoeno lpyruvate
2 -phosphoglyceric ac id
3 -phosphoglyceric ac id
PO POP
ppGpp
PPO
pppGpp
RNA
RuDP
TEMED
TLC
Tr i c in e
Tr i s
1 , 4 -bi s[2 ( 5 -phenylox a z o l y l )]Benzene
guano s ine 5 ' -d ipho sphate- 3 ' -d ipho sphate
2 , 5 -diphenyloxazole
guanos ine 5 ' -triphosphat e- 3 ' -d ipho sphate
r ibonucleic ac id
ribu lose 1 , 5 -diphosphat e
N , N , N ' , N'-Tetramethylethy lened iamine
thin-layer chromatography
N -tris[Hydroxymethyl]-methyl glyc ine
t r i s ( hydroxymethyl ) aminomethane
vi
vii
TABLE OF CONTENTS
AB STRACT i i
ACKNOWLEDGEMENTS iv
L I ST OF ABBREVIAT IONS
TABLE OF CONTENTS
L I ST OF F I GURES
LIST OF TABLES
CHAPTER 1 INTRODUCT ION
1 . 1 General Background
V
Vll
x i i i
xvi i i
1
1 . 2 Acety l -CoA Carboxylase from An imal Sources
1 . 2 . 1 Mo lecu lar prope rties 2
1 . 2 . 2 Regu lat ion o f cata lytic activity
1 . 2 . 2 . 1 Long-term control o f
acetyl-CoA carboxylase 2
1 . 2 . 2 . 2 Short-term control of
acetyl -CoA carboxy lase 4
1 . 3 Acetyl -CoA Carboxylase from Escherichia col i
1 . 3 . 1 Molecular propert ies 8
1 . 3 . 2 Regulat i on o f cata lytic act iv ity 9
1 . 4 Acetyl -CoA Carboxylase from Yea st 10
1 . 5 Acet y l-CoA Carboxyl ase f rom Plant s 1 1
1 . 6 Acetyl -CoA Carboxylase from Other S ources 1 2 .
1 . 7 Acety l -CoA Carboxylase a s a B iot in Enzyme 1 4
1 . 8 Fatty Ac id Biosynthe s i s in Plants 1 5
CHAPTER 2 MATERIALS
2 . 1 P lant Mater i a l s 2 0
CHAPTER
viii
2.2 Reage nts
3 METHODS
3.1 Preparation o f Acy l -CoA Esters
3.2 En z yme Assays
3. 3 Preparation o f C e l l - free Extracts
3. 4 Preparation o f Chloropl asts
3.5 Preparation o f Me sophyl l Protop lasts and
Bund le Sheath Strand s
3. 6 Preparation o f E . co l i Acety l-CoA Carbox
lase Component s
3.7 I ncorporation o f [ l - 1 �C ] Acetate into Lipids
3. 7. 1 [ l - 1 4C ] acetate incorporat ion into
2 0
2 2
2 3
2 5
2 6
2 6
2 8
lipids by i solated chloroplasts 2 9
3. 7. 2 [ l- 1 4C] acetate incorporat i on into
l ipids by leaf s l i ces
3. 8 Preparation of Ma i z e Lea f Section s
3. 9 Preparation o f S epharo se -N-Propane
3.1 0 Polyacry lamide Ge l Electrophere s i s
3.1 1 Centr ifugat ion
3.1 2 Ana l yti cal Methods
3.1 2. 1 Determinat i on o f prote in
3.1 2. 2 Determinat i on of chlorophy l l
3.1 3 Determination o f Radi oact ivity
3.1 4 Chromatographic P rocedure s
3.1 4. 1 Gel f i ltrat ion chromatography
3.1 4. 2 Thin�layer chromatography
3.1 4. 3 P aper chromatography
3.1 5 Pur i f i cation o f Acetyl-CoA Carboxylase
from Leave s
2 9
3 0
3 0
3 0
3 1
3 2
3 2
3 3
3 3
3 3
3 3
3 4
CHAPTER 4 RESULTS
GENERAL FEATURE S AND STAB I LITY OF LEAF
ACETYL-CoA CARBOXYLASE
4.1 General Feature s of Acetyl -CoA Carboxy
lase Act iv ity
4.2 Stab i l i zat ion o f Acetyl -CoA Carboxylase
in Ce l l -Free Extract s by Sul fhydryl Pro
tect ing Agent s
LOCAT I ON OF ACETYL-CoA CARBOXYLASE ACTIVITY
IN MAI Z E LEAVES
4 . 3 Locat ion of Acety l -CoA Carboxy lase in
Chlorop last s o f Ma i z e Leave s
4. 4 Solub i l ity o f Ma i z e Chloropl astic Acetyl
CoA Carboxylase
4 . 5 Location o f the B iot in Prosthetic Group
ix
3 6
4 2
4 6
4 8
o f Chloroplast i c Acetyl -CoA Carboxylase 5 1
4. 6 Distr ibut ion o f Ac ety l -CoA Carboxyl a s e
Between Mesophy l l and Bund le She at h C e l l s
o f Mai z e Leave s
LEVELS OF ACETYL-CoA CARBOXYLASE ACTIVITY IN
LEAVES
4 . 7 I nve st igat ion o f the Re lat ionship B etween
Leaf Deve lopment , Acetyl -CoA Carboxylase
Activity and [ l - 1 4C] acetate Incorpor ation
5 5
into Lipids 5 5
4. 7.1 I ncorporat ion o f [ l- 1 ljC] acetate
by ma i z e l e a f s l ic e s 6 0
4. 7. 2 I ncorporat i on o f [ l - 14 C J acetate
into l ip i d s by i solated chloro
p l a sts from deve loping ma ize
l eave s
4.7.3 Acetyl -CoA carboxylase activity
in c e l l - free extract s of deve lop
ing mai ze l eaves
6 0
6 2
4 . 7 . 4 Acety l -CoA carboxylase act ivity in
isolated chloropla st s from deve lop
ing ma i z e leave s
4 . 8 Acetyl-CoA Carboxyla se Activity and Lipid
Synthe s i s in Leave s o f Ma i z e , Barley and
X
6 5
Spinach 6 5
4 . 9 E f fect o f Light on Ac etyl-CoA Carboxylase
Act ivity in Ma i z e Leave s
PURIFICATI ON OF LEAF ACETYL-CoA CARBOXYLASE
4 . 1 0 Pur i f ic at ion o f Acety l -CoA Carboxy l a s e
from Ma i z e Leave s
4 . 1 1 Pur i f i c at ion o f Ac etyl -CoA Carboxy lase
from Barley Leave s
K I NET IC PROPERT IES OF ACETYL-CoA CARBOXYLASE
4 . 1 2 E f fect of Acety l -CoA and HC03 Concentra-
7 0
7 0
8 3
t ions on Acetyl -CoA Carboxylase Act ivity 8 4
4 . 1 3 E f f ect o f ATP and MgC12 Concentrat ions
on Acety l -CoA Ca rboxylase Act iv ity
4 . 1 4 Spec i f i c ity of the Divalent Metal Ion
Requi red for Acety l-CoA Carboxylase
Act ivity
4 . 1 5 E f fect of pH on Acetyl -CoA Carboxylase
Act ivity
4 . 1 6 E f fect of Temperature on Acetyl -CoA
Carboxyl a se Act ivity
4 . 1 7 Act ivation of Acetyl -CoA Carboxylase
Activity by Monova l ent Cat ions
4 . 1 8 S ubstrate Spec i f i c ity of Acetyl-CoA
Carboxy l a s e
4 . 1 9 I nhibition o f Ma i z e L e a f Acetyl - CoA
Carboxylase by Ma lonyl -CoA
9 2
1 0 5
1 0 5
1 0 7
1 0 7
1 1 1
1 1 1
4 . 2 0 Effect o f ADP on Acety l -CoA Carboxy lase
Act ivity
4 . 2 1 E f fect of CoA on Acetyl -CoA Carboxyl a s e
Act ivity
4 . 2 2 E f f ect of Palrnitoyl -CoA on Acetyl -CoA
Carboxy l a s e Act ivity
4 . 2 3 E ffect of AMP , Pho sphoenolpyruvate ,
Oxaloacet ate and Citrate on Acetyl -CoA
Carboxyla s e Act ivity
4 . 2 4 E f f ect o f Sul fhydryl Reacting Reagent s
on Acetyl -CoA Carboxylase Act ivity
CHAPTER 5 DI SCUS S I ON
5 . 1 Acetyl-CoA Carboxylase - it s General
Feature s a nd Stabi l ity
5 . 2 Cellular Location o f Acetyl-CoA Carboxy
lase in Ma i ze Le ave s
5 . 3 Re l ationship Between Acetyl-CoA Carboxy
l ase Act iv ity and Lipid Synthe s i s in
I so l ated Ch loropl a st s
5 . 4 Re lation sh i p Between Acetyl-CoA Carboxy
lase Act ivity , Lipid Synthe s i s and Lea f
Deve lopment
x i
1 1 6
1 1 6
1 2 5
1 2 5
1 2 8
1 3 0
1 3 2
1 3 5
1 3 7
5 . 5 Pur i f icat ion o f Acety l -CoA Carboxylase 1 3 9
5 . 6 K inetic Properties o f Acetyl-CoA Carboxy-
lase
5 . 6 . 1 E f f e ct of sub strate s on acety l -CoA
carboxylase 1 4 2
5� 6 . 2 Sub strate spec i f icity o f acetyl -
CoA c arboxy lase
5 . 6 . 3 E f fectors o f acety l-CoA c arboxy
l a s e a ctivity
5 . 7 L i ght-Dark Modulation o f Acetyl - CoA
Carboxy l a s e Act ivity
1 4 3
1 4 4
1 4 6
x i i i
LI ST O F FIGURE S
F igure Page
1 Structura l c l a s s i f ication of biot in c ontaining
e n zyme s
2 I dent i f icat i on o f the product of acetyl -CoA
c arboxy l a s e as say by TLC
3 Identificat ion o f the product of the acety l -
1 6
3 7
CoA carbox y l ase a s say by paper chromatography 3 8
4 Dependence o f acetyl -CoA c arboxylase activity
on protein l eve l s of cell- free extracts o f
mai ze leave s
5 E f fect o f t ime on acetyl-CoA carboxyl a s e
4 0
act ivity i n c e l l - free extracts of ma i z e leaves 4 1
6 Stab i l i z at ion o f acetyl -CoA carboxylase act iv
ity in ce l l - free extracts of ma ize by 8 -mer-
c aptoethano l 4 3
7 Stabi l i zat i on o f acetyl -CoA carboxylase act iv
ity in cel l - free extracts of barley by 8 -mer
c aptoethano l
8 D i stribut ion o f enzymes , chlorophy l l and pro
te in fol lowing the centrifugat ion of pur i f ied
ma i ze chloropl ast s in a suc ro s e density
gradient
9 Repre sentat ive f i e ld o f a preparation o f i so
l ated mai z e chloroplasts
4 4
4 7
4 9
x iv
Figure Page
1 0 D i str ibut ion o f enzyme s , chlorophy l l and
prote in f o l lowing the centri fugation of d i s
rupted ma i z e chlorop l asts i n a di scont i nuou s
sucro se den s ity gradient 5 0
1 1 Representat ive f i e ld o f a preparation o f iso
l ated mai z e me sophyl l protopl ast s
1 2 Representat ive f i e ld o f a preparation o f mai z e
5 8
bundle sheath strands 5 9
1 3 E f fect o f l ight on the activity o f acety l -CoA
c arboxyla s e in ma i z e leave s
1 4 E lut ion o f a c etyl -CoA carboxylase of ma i z e from
S epharo se-N -Propane
1 5 Ge l f i ltrat ion o f acety l -CoA carboxy l a s e o f
ma i z e on U lt rogel AcA2 2
1 6 Ge l f i ltrat i on o f acetyl -CoA carboxy l a s e o f
mai z e on U ltrogel AcA2 2
1 7 Polyacrylamide gel e l ectropher e s i s o f acetyl
CoA c arboxyl as e o f ma i z e l eave s
1 8 Rel at ionship b etween HC03 , acetyl-CoA concen
trat i ons and the activity o f ma i ze leaf
acet y l-CoA c arboxylase
1 9 Re l at ionship between HC03 , acety l-CoA concen
trat ions and the activity o f bar l ey leaf
acetyl -CoA carboxylase
2 0 Lineweaver -Burk analy s i s o f the e f fect o f
acetyl -CoA on the activity o f maize leaf
acet y l-CoA c arboxy lase
7 1
7 7
7 8
8 0
8 1
8 6
8 7
8 8
XV
Figure Page
2 1 Lineweaver -Burk analy s i s o f the e f fect o f
acety l -CoA o n t h e act ivity o f bar ley l e a f
acety l - CoA carboxy lase
2 2 Re l at ionshi p between HC03 , acety l -CoA concen
trat ions and the activity o f ma i z e leaf
acety l - CoA carboxyl ase
2 3 Re lat ionship be tween HC03 , ac etyl -CoA conc en
trat ions and the activity of bar ley l e a f
acetyl -CoA c arboxylase
2 4 Lineweaver -Burk analy s i s o f the e f fect o f
HCO� o n the activity o f ma i z e leaf acetvl-CoA �
carbox y l a s e
2 5 Lineweaver -Burk a naly s i s o f the e f fect o f
HCO� on the activity of bar ley leaf acetyl -CoA
carboxylase
2 6 Effect o f MgC 1 2 o n the act ivity o f ma i z e leaf
acety l - CoA carboxylase
2 7 Effect o f MgC l 2 o n the act ivity o f barley l e a f
acetyl -CoA carboxylase
2 8 Ef fect o f ATP o n the act ivity o f ma i z e leaf
acety l - CoA c arboxylase
2 9 E f fect o f ATP on the activity o f bar ley leaf
acety l-CoA carboxy lase
3 0 Re lationship between ATP , MgC l 2 concentration s
and t h e activity o f mai z e l e a f acety l - CoA
carbox y l a s e
8 9
9 0
91
9 3
9 4
9 5
9 6
9 7
9 8
1 0 0
xvi
Figure Page
3 1 Re l ation ship between ATP , MgC l2 concentrations
and the act ivity of barley leaf acety l -CoA
carboxy l a s e
3 2 Ana ly s i s b y Hil l -plot of the relation s h ip be
tween ATP , MgC12 concentrat ions and the
activity of ma ize l e a f acetyl -CoA carboxylase
3 3 Ana ly s i s by Hill-plot o f the re lat ions h ip be
tween ATP , MgC l2 concentrat ions and the activ-
1 0 1
1 0 2 , 1 0 3
i ty o f bar l ey leaf acetyl-CoA carboxyl a s e 1 0 4
3 4 E f fect o f d iva lent metal ions o n the a c t ivity
o f ma i z e l ea f acety l -CoA carboxylase
3 5 E ffect o f pH on the act ivity o f ma i z e l e a f
acety l -CoA c arboxy l a se
3 6 E f fect o f pH on the act ivity o f bar l ey l e a f
acetyl -CoA carboxyl a s e
3 7 E f fect o f temperature on the activity o f ma i z e
1 0 6
1 0 8
1 0 9
l e a f acetyl -CoA c arboxylase 1 1 0
3 8 E f fect o f KCl on the activity o f ma i z e l e a f
acety l -CoA carboxylase
3 9 Spec ific ity of carboxylation by ma i z e l e a f
a c e tyl -CoA carboxylase
4 0 E f fect o f malonyl-CoA on the activity o f mai z e
l e a f acetyl -CoA carboxylase
4 1 ADP inhibition o f the ac tivity o f ma i z e l e a f
acetyl-CoA carboxylase
1 1 2
1 1 4
1 1 5
1 1 7
xv ii
F igure Page
4 2 L i neweaver-Burk analys i s o f the e f fect o f ADP
on the activity o f ma i z e leaf acety l-CoA
c arboxylase
4 3 Ana l y s i s by Dixon-plot o f the e f fect o f ADP
�n the act ivity o f ma i z e leaf acety l - CoA
c arboxylase
4 4 ADP inhibi t ion o f the a ctivity o f ma i z e l e a f
acety l -CoA c arboxyl a s e
4 5 L ineweaver-Burk ana l y s i s of the e f fect o f ADP
o n the act ivity o f ma i z e leaf acetyl-CoA
c arboxylase
4 6 CoA inhibition o f the activity o f ma i z e leaf
acetyl -CoA carboxyl ase
4 7 L ineweaver-Burk ana ly s i s of the ef fect o f CoA
o n the act ivity of ma i z e leaf a cety l - CoA car-
1 1 8
1 1 9
1 2 0
1 2 1
1 2 2
boxylase 1 2 3
4 8 Ana l y s i s by D ixon-plot o f the e f fect o f CoA
o n the activ ity o f ma i z e leaf acety l - CoA car-
boxy l ase 1 2 4
4 9 P a lmitoyl -CoA inhibition of the activity o f
ma i z e leaf acetyl-CoA c arboxylase
5 0 L i neweaver -Burk analys i s of the e f f ec t o f
pa lmitoyl-CoA on the activity o f ma i z e leaf
acetyl-CoA c arboxylase
1 2 6
1 2 7
xv i ii
Table
I
L I ST OF TABLES
Protomer-polyrner tran s i t ion of an imal
acetyl -CoA carboxylase
I I Co f actor requ irements o f acetyl-CoA c arboxy-
5
l a s e activity in cel l - free extracts o f ma i z e 3 9
I l l Ace ty l -CoA c arboxylase ac t ivity i n c e l l - free
extracts o f sp inach l eave s
IV
V
Preparation o f biot in c arboxylase from E . coli
Co f ac tor requ i rements for the carboxylation of
the biotin pro s thetic group in ma i z e chloro
p l a s t s by biot i n c arboxylase of E. col i
VI Ma l onyl -CoA format ion from carboxyl -biotin by
mai z e chloropl a st s
VI I D i s t r ibut ion o f the biotin pro sthet ic group in
chloroplasts i so l ated from the leave s o f three
4 5
5 2
5 3
5 4
p l an t s 5 6
VI I I D i s tribution o f en zymes between me sophy l l proto-
p l a s t s and bundle sheath s trand s 5 7
IX E f fe c t of leaf deve lopment on [l - 1 4 C ] acetate
incorporation into l ip i d s by leaf s l i c e s of
ma i z e ·
X E f fect of l ea f deve lopment on [l - 1 4C ] acetate
incorporat ion i nto l ipids by i sol ated chloro
p l a s t s of mai z e
6 1
6 3
Tabl e
XI Acety l-CoA carboxylase act ivity in c e l l - free
extracts obta ined from section s of maize
leave s
XI I Acetyl -CoA carboxylase act ivity in c hloro-
xix
6 4
pl ast s isolated from sect i ons o f ma i ze leave s 6 6
XI I I [l- 1'"'C J acetate incorporat ion into l ipids o f
chloropl asts and acetyl -CoA carboxyla se
act iv ities in c e l l - free extracts and chloro
pl ast s from ma i z e , bar l ey and spinach
XIV Acety l-CoA carboxylase in ma i z e and spinach
leave s
XV Pur i f ication o f acetyl-CoA carboxylase of
ma i z e leave s us ing procedure I
XVI Pur i f ication o f acety l-CoA carboxy lase of ma i z e
leave s us ing proc edure I I
XVI I
XVI I I
I nte ract ion of ac etyl-CoA c arboxyl ase with
Sepharo se-N-Cx
Stabil ity of part ially pur i f ied ac etyl -CoA
carboxylase
XIX Pur i f ication o f acetyl-CoA carboxyl a s e of
barley leave s u s i ng procedure I
XX Act ivation of ma i z e lea f acetyl-CoA c arboxy
lase by monovalent cat ions
XXI Inhibition of ma i z e leaf ac etyl -CoA c arboxy-
6 7
6 9
7 3
7 4
7 5
8 2
8 5
1 1 3
lase act ivity b y sulfhydryl reacting reagent s 1 2 9
top related