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Information on EC 2.4.1.18 - 1,4-alpha-glucan branching enzyme and Organism(s) Zea mays and UniProt Accession O81387
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2.4.1.18 1,4-alpha-glucan branching enzymeIUBMB Comments
Converts amylose into amylopectin. The accepted name requires a qualification depending on the product, glycogen or amylopectin, e.g. glycogen branching enzyme, amylopectin branching enzyme. The latter has frequently been termed Q-enzyme.
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Word Map
- 2.4.1.18
- biloba
- ginkgo
- amylopectin
- endosperm
- maize
- grain
-
pyrophosphorylase
- phosphorylase
-
granule-bound
- glucans
- potato
-
debranching
- polysaccharide
-
polyglucosan
-
herbal
- ssiia
-
ginkgolide
- kernel
- gelatin
-
waxy
- glycogenosis
- amyloplasts
- pullulanase
- andersen
- dextrin
- isoamylase
- bilobalide
- agpase
-
high-amylose
-
amylolytic
-
chain-length
-
lafora
-
rhodothermus
- biotechnology
- medicine
- adpglucose
- glycogenin
- food industry
- nutrition
-
diastase-resistant
- alpha-glucans
- drug development
-
pas-positive
- isorhamnetin
The taxonomic range for the selected organisms is: Zea mays
The enzyme appears in selected viruses and cellular organisms
The enzyme appears in selected viruses and cellular organisms
Synonyms
gbe, branching enzyme, sbeiib, glycogen branching enzyme, starch branching enzyme, sbeiia, beiib, sbeii, starch-branching enzyme, beiia, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
alpha-1,4-glucan:alpha-1,4-glucan 6-glycosyltransferase
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-
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alpha-1,4-glucan:alpha-1,4-glucan-6-glycosyltransferase
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-
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alpha-glucan-branching glycosyltransferase
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-
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amylo-(1,4-1,6)-transglycosylase
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-
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amylose isomerase
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-
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BE
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-
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branching factor, enzymatic
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-
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branching glycosyltransferase
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-
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enzyme Q
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GBE
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-
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glucosan transglycosylase
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glycogen branching enzyme
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glycosyltransferase, alpha-glucan-branching
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Q-enzyme
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QE
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SBE
starch branching enzyme
starch branching enzyme IIb
SBE
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-
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starch branching enzyme
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REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
glycosyl group transfer
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-
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-
PATHWAY SOURCE
PATHWAYS
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-, -, -, -
SYSTEMATIC NAME
IUBMB Comments
(1->4)-alpha-D-glucan:(1->4)-alpha-D-glucan 6-alpha-D-[(1->4)-alpha-D-glucano]-transferase
Converts amylose into amylopectin. The accepted name requires a qualification depending on the product, glycogen or amylopectin, e.g. glycogen branching enzyme, amylopectin branching enzyme. The latter has frequently been termed Q-enzyme.
CAS REGISTRY NUMBER
COMMENTARY
9001-97-2
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SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
amylose
amylose containing alpha-1,6-glucosidic linkages
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initially the three isoenzymes BE I, BE IIa and BE IIb produce chains of various sizes, DP approximately 8 to 200. Isoenzyme BE I preferentially transfers longer chains than isoenzyme IIa and IIb
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-
?
additional information
?
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in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
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-
?
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
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-
?
additional information
?
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in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
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?
additional information
?
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the catalytic center is exclusively located in the central position of the enzyme
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?
additional information
?
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chain-length distribution and branch linkage frequence of the 3 isoenymes
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?
additional information
?
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the conserved Arg residue 384 plays an important role in the catalytic function but may not be directly involved in substrate binding
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?
additional information
?
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starch-branching enzyme and glycogen synthase work in a cyclically interdependent fashion
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?
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
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-
?
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
-
-
?
additional information
?
-
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
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-
?
additional information
?
-
the enzyme performs branching of two linear alpha-(1,4)-D-glucans substrates of degrees of polymerization about 150 and 6000, product identification by NMR and gel filtration, determination of chain-length distributions and hydrodynamic volume distributions, interchain mechanism, overview
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?
additional information
?
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the enzyme performs branching of two linear alpha-(1,4)-D-glucans substrates of degrees of polymerization about 150 and 6000, product identification by NMR and gel filtration, determination of chain-length distributions and hydrodynamic volume distributions, interchain mechanism, overview
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-
?
additional information
?
-
molecular weight distribution of starch, amylose and amylopectin, overview. SBE is the only enzyme that generates glucan branches, i.e. it is the only chain-stopping substance for branch growth, and as a consequence SBE has a significant effect on the final structure of the resulting starch
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?
additional information
?
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molecular weight distribution of starch, amylose and amylopectin, overview. SBE is the only enzyme that generates glucan branches, i.e. it is the only chain-stopping substance for branch growth, and as a consequence SBE has a significant effect on the final structure of the resulting starch
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-
?
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
-
-
?
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
-
-
?
additional information
?
-
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
-
-
?
additional information
?
-
-
starch-branching enzyme and glycogen synthase work in a cyclically interdependent fashion
-
-
?
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
-
-
?
additional information
?
-
in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
-
-
?
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
10
amylose
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reduced amylose of an average chain-length 405, enzyme isoenzyme BE IIa
11
amylose
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reduced amylose of an average chain-length 405, enzyme isoenzyme BE IIb
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
malfunction
inhibitory effects of these hpSBEIIRNA constructs on the expression of SBEIIa and SBEIIb in maize endosperm, levels of ZmSBEII transcription and SBE activity in kernels of transgenic plants, overview. The transgenic maize lines show increased content of amylopectin chains with high-molecular weight compared to decreased low-molecular weight chains
malfunction
inhibitory effects of these hpSBEIIRNA constructs on the expression of SBEIIa and SBEIIb in maize endosperm, levels of ZmSBEII transcription and SBE activity in kernels of transgenic plants, overview. The transgenic maize lines show increased content of amylopectin chains with high-molecular weight compared to decreased low-molecular weight chains
metabolism
-
granule-bound proteins involved in amylopectin synthesis are partitioned into the starch granule as a result of their association within protein complexes, and strach synthase IIa plays a crucial role in trafficking starch synthase I and starch branching enzyme IIb into the granule matrix. A mutant starch synthase IIa that has lost catalytic activity and is inable to bind to starch additionally leads to greatly reduced activities of starch synthase I and starch branching enzyme IIb
physiological function
additional information
physiological function
SBE is the only enzyme that generates glucan branches, i.e. it is the only chain-stopping substance for branch growth, and as a consequence SBE has a significant effect on the final structure of the resulting starch
physiological function
starch branching enzyme IIb plays a crucial role in amylopectin biosynthesis in maize endosperm by defining the structural and functional properties of storage starch and is regulated by protein phosphorylation
additional information
molecular dynamics simulation and modeling of phosphorylation of enzyme mutants
additional information
-
molecular dynamics simulation and modeling of phosphorylation of enzyme mutants
additional information
Tyr352, Glu513, and Ser349 are important for mSBEIIa activity while Arg456 is important for determining the position at which the linear glucan is cut, enzyme active site structure, molecular dynamics simulations and modeling, overview
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
phosphoprotein
native and recombinant maize SBEIIb are used as substrates for amyloplast protein kinases to identify phosphorylation sites on the protein, bioinformatics, site-directed mutagenesis, and mass spectrometry identify three phosphorylation sites at Ser residues: Ser649, Ser286, and Ser297. Ca2+-dependent protein kinases from amyloplasts, termed K1, responsible for Ser649 and Ser286 phosphorylation, and K2, responsible for Ser649 and Ser297 phosphorylation. The Ser286 and Ser297 phosphorylation sites are conserved in all plant branching enzymes and are located at opposite openings of the 8-stranded parallel beta-barrel of the active site, which is involved with substrate binding and catalysis. Molecular dynamics simulation analysis indicates that phospho-Ser297 forms a stable salt bridge with Arg665, part of a conserved Cys-containing domain in plant branching enzymes. Ser649 conservation appears confined to the enzyme in cereals and is not universal, and is presumably associated with functions specific to seed storage
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
E513D
site-directed mutagenesis, the mutant shows a much lower activity compared to wild-type enzyme mSBEIIa
R363K
site-directed mutagenesis, the mutant shows similar activity as the wild-type enzyme mSBEIIa
R456K
site-directed mutagenesis, the mutant shows similar activity compared to wild-type enzyme mSBEIIa
S349F
site-directed mutagenesis, creates an additional binding site for glucose, the mutant shows a much lower activity compared to wild-type enzyme mSBEIIa
Y352F
site-directed mutagenesis, , the mutant shows a much lower activity compared to wild-type enzyme mSBEIIa
additional information
additional information
application of RNAi technology for improving amylose content in maize endosperm through the suppression of the ZmSBEIIa and ZmSBEIIb genes by hairpin SBEIIRNAi constructs. These SBEIIRNAi transgenes lead to the downregulation of ZmSBEII expression and SBE activity to various degrees and altered the morphology of starch granule
additional information
application of RNAi technology for improving amylose content in maize endosperm through the suppression of the ZmSBEIIa and ZmSBEIIb genes by hairpin SBEIIRNAi constructs. These SBEIIRNAi transgenes lead to the downregulation of ZmSBEII expression and SBE activity to various degrees and altered the morphology of starch granule
additional information
-
application of RNAi technology for improving amylose content in maize endosperm through the suppression of the ZmSBEIIa and ZmSBEIIb genes by hairpin SBEIIRNAi constructs. These SBEIIRNAi transgenes lead to the downregulation of ZmSBEII expression and SBE activity to various degrees and altered the morphology of starch granule
additional information
application of RNAi technology for improving amylose content in maize endosperm through the suppression of the ZmSBEIIa and ZmSBEIIb genes by hairpin SBEIIRNAi constructs. These SBEIIRNAi transgenes lead to the downregulation of ZmSBEII expression and SBE activity to various degrees and altered the morphology of starch granule
additional information
application of RNAi technology for improving amylose content in maize endosperm through the suppression of the ZmSBEIIa and ZmSBEIIb genes by hairpin SBEIIRNAi constructs. These SBEIIRNAi transgenes lead to the downregulation of ZmSBEII expression and SBE activity to various degrees and altered the morphology of starch granule
additional information
-
application of RNAi technology for improving amylose content in maize endosperm through the suppression of the ZmSBEIIa and ZmSBEIIb genes by hairpin SBEIIRNAi constructs. These SBEIIRNAi transgenes lead to the downregulation of ZmSBEII expression and SBE activity to various degrees and altered the morphology of starch granule
additional information
construction of enzyme point mutants by site-directed mutagenesis to change the chain-length distribution CLD by changing activity of enzyme SBE. The enzyme mutants show no or only a slight change in degree of polymerization of branched glucans
additional information
-
construction of enzyme point mutants by site-directed mutagenesis to change the chain-length distribution CLD by changing activity of enzyme SBE. The enzyme mutants show no or only a slight change in degree of polymerization of branched glucans
additional information
generation of N- and C-terminally truncated enzyme mutants. Activities of kinases on wild-type and enzyme mutants, overview
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
recombinant N-terminally His6-tagged wild-type and mutant enzymes from Escherichia coli strain BL21(DE3)pLysS by nickel affinity chromatography
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli, chimeric enzymes consisting of part mBE I and mBE II
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expression in Saccharomyces cerevisiae, each of the three isoforms is functional in yeast cells
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gene Sbe2a, recombinant expression of N-terminally His6-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3)pLysS
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
biotechnology
RNAi technology is applied to suppress the expression of starch branching enzyme IIa and IIb and to increase amylose content in maize endosperm, and stably inherit high-amylose maize lines. Transgenic maize lines with amylose content of up to 55.89% are produced, which avoid the significant decreases in starch content and grain yield that occur in high-amylose starch branching enzyme IIb gene mutant
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Takeda, Y.; Guan, H.P.; Preiss, J.
Branching of amylose by the branching isoenzymes of maize endosperm
Carbohydr. Res.
240
253-263
1993
Zea mays
-
Baba, T.; Arai, Y.; Ono, T.; Munakata, A.; Yamaguchi, H.; Itoh, T.
Role of the recessive amylose-extender allele in starch biosynthesis of maize. Part II. Branching enzyme from amylomaize endosperms
Carbohydr. Res.
107
215-230
1982
Zea mays
-
Boyer, C.D.; Preiss, J.
Multiple forms of 1,4-alpha-D-glucan, 1,4-alpha-D-glucan-6-glycosyl transferase from developing Zea mays L. kernels
Carbohydr. Res.
61
321-334
1978
Zea mays
-
Libessart, N.; Preiss, J.
Arginine residue 384 at the catalytic center is important for branching enzyme II from maize endosperm
Arch. Biochem. Biophys.
360
135-141
1998
Zea mays
Kuriki, T.; Stewart, D.C.; Preiss, J.
Construction of chimeric enzymes out of maize endosperm branching enzymes I and II: activity and properties
J. Biol. Chem.
272
28999-29004
1997
Zea mays
Seo, B.S.; Kim, S.; Scott, M.P.; Singletary, G.W.; Wong, K.S.; James, M.G.; Myers, A.M.
Functional interactions between heterologously expressed starch-branching enzymes of maize and the glycogen synthases of Brewer's yeast
Plant Physiol.
128
1189-1199
2002
Zea mays
Gao, M.; Fisher, D.K.; Kim, K.N.; Shannon, J.C.; Guiltinan, M.J.
Evolutionary conservation and expression patterns of maize starch branching enzyme I and IIb genes suggests isoform specialization
Plant Mol. Biol.
30
11223-11232
1996
Zea mays
-
Gao, M.; Fisher, D.K.; Kim, K.N.; Shannon, J.C.; Guiltinan, M.J.
Independent genetic control of maize starch-branching enzymes IIa and IIb. Isolation and characterization of a 2a cDNA
Plant Physiol.
114
69-78
1997
Zea mays
Yao, Y.; Thompson, D.B.; Guiltinan, M.J.
Maize starch-branching enzyme isoforms and amylopectin structure. In the absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching
Plant Physiol.
136
3515-3523
2004
Zea mays (O24421), Zea mays (O81387), Zea mays
Hernandez, J.M.; Gaborieau, M.; Castignolles, P.; Gidley, M.J.; Myers, A.M.; Gilbert, R.G.
Mechanistic investigation of a starch-branching enzyme using hydrodynamic volume SEC analysis
Biomacromolecules
9
954-965
2008
Zea mays (O24421), Zea mays
Liu, F.; Romanova, N.; Lee, E.A.; Ahmed, R.; Evans, M.; Gilbert, E.P.; Morell, M.K.; Emes, M.J.; Tetlow, I.J.
Glucan affinity of starch synthase IIa determines binding of starch synthase I and starch branching enzyme IIb to starch granules
Biochem. J.
448
373-387
2012
Zea mays
Makhmoudova, A.; Williams, D.; Brewer, D.; Massey, S.; Patterson, J.; Silva, A.; Vassall, K.A.; Liu, F.; Subedi, S.; Harauz, G.; Siu, K.W.; Tetlow, I.J.; Emes, M.J.
Identification of multiple phosphorylation sites on maize endosperm starch branching enzyme IIb, a key enzyme in amylopectin biosynthesis
J. Biol. Chem.
289
9233-9246
2014
Zea mays (Q08047), Zea mays, Zea mays CG102 (Q08047)
Zhao, Y.; Li, N.; Li, B.; Li, Z.; Xie, G.; Zhang, J.
Reduced expression of starch branching enzyme IIa and IIb in maize endosperm by RNAi constructs greatly increases the amylose content in kernel with nearly normal morphology
Planta
241
449-461
2015
Zea mays (O24421), Zea mays (O81387), Zea mays
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