Information on EC 2.4.1.21 - starch synthase (glycosyl-transferring)

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The expected taxonomic range for this enzyme is: Bacteria, Eukaryota, Archaea

EC NUMBER
COMMENTARY hide
2.4.1.21
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RECOMMENDED NAME
GeneOntology No.
starch synthase (glycosyl-transferring)
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
ADP-alpha-D-glucose + [(1->4)-alpha-D-glucosyl]n = ADP + [(1->4)-alpha-D-glucosyl]n+1
show the reaction diagram
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-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hexosyl group transfer
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-
-
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Biosynthesis of secondary metabolites
-
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glycogen biosynthesis I (from ADP-D-Glucose)
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glycogen metabolism
-
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Metabolic pathways
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Starch and sucrose metabolism
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starch biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
ADP-glucose:(1->4)-alpha-D-glucan 4-alpha-D-glucosyltransferase
The accepted name varies according to the source of the enzyme and the nature of its synthetic product, e.g. starch synthase, bacterial glycogen synthase. Similar to EC 2.4.1.11 [glycogen(starch) synthase] but the preferred or mandatory nucleoside diphosphate sugar substrate is ADP-alpha-D-glucose. The entry covers starch and glycogen synthases utilizing ADP-alpha-D-glucose.
CAS REGISTRY NUMBER
COMMENTARY hide
9030-10-8
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
-
-
Manually annotated by BRENDA team
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UniProt
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
NRRL B1973
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-
Manually annotated by BRENDA team
Arthrobacter sp. NRRL B1973
NRRL B1973
-
-
Manually annotated by BRENDA team
var. esculenta
-
-
Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
strain 11 h
SwissProt
Manually annotated by BRENDA team
strain 11 h
SwissProt
Manually annotated by BRENDA team
castor bean
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
grape
-
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Manually annotated by BRENDA team
teosinte
-
-
Manually annotated by BRENDA team
Zea saccharata
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
metabolism
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
ADP-glucose + (1,4-alpha-D-glucosyl)n
ADP + (1,4-alpha-D-glucosyl)n+1
show the reaction diagram
ADP-glucose + (1,4-alpha-glucosyl)n
ADP + (1,4-alpha-glucosyl)n+1
show the reaction diagram
ADP-glucose + 6'''-alpha-maltotriosyl-maltohexaose
ADP + 6''''-alpha-maltotetrasyl-maltohexaose
show the reaction diagram
-
-
starch synthase II elongates only the maltotriose chain
?
ADP-glucose + alpha-1,4-polyglucan
ADP + alpha-1,4-polyglucan
show the reaction diagram
ADP-glucose + amylopectin
ADP + ?
show the reaction diagram
ADP-glucose + glycogen
ADP + ?
show the reaction diagram
ADP-glucose + maltopentaose
ADP + maltohexaose
show the reaction diagram
-
-
granule-bound starch synthase I, smaller amounts of longer malto-oligosaccharides are also produced suggesting that starch synthase I adds 1 or more glucose units to the primer
?
ADP-glucose + maltose
ADP + maltotriose + maltotetraose
show the reaction diagram
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-
-
?
ADP-glucose + maltotriose
ADP + maltotetraose
show the reaction diagram
ADP-glucose + [(1->4)-alpha-D-glucosyl]n
ADP + [(1->4)-alpha-D-glucosyl]n+1
show the reaction diagram
dADPglucose + alpha-1,4-polyglucan
dADP + alpha-1,4-polyglucan
show the reaction diagram
methyl-6'-alpha-maltosyl-alpha-maltotrioside + ADP-glucose
?
show the reaction diagram
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SSII catalyses an equimolar and non-processive elongation reaction of this substrate. Both of the non-reducing ends of methyl 6'-alpha-maltosyl-6'-maltotrioside are extended equally resulting in two hexasaccharide products in nearly equal amounts
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-
?
n ADP-glucose
n ADP + [(1-4)-alpha-D-glucosyl]n
show the reaction diagram
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-
-
-
?
UDP-glucose + (1,4-alpha-D-glucosyl)n
UDP + (1,4-alpha-D-glucosyl)n+1
show the reaction diagram
additional information
?
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
ADP-glucose + (1,4-alpha-D-glucosyl)n
ADP + (1,4-alpha-D-glucosyl)n+1
show the reaction diagram
ADP-glucose + (1,4-alpha-glucosyl)n
ADP + (1,4-alpha-glucosyl)n+1
show the reaction diagram
ADP-glucose + alpha-1,4-polyglucan
ADP + alpha-1,4-polyglucan
show the reaction diagram
ADP-glucose + [(1->4)-alpha-D-glucosyl]n
ADP + [(1->4)-alpha-D-glucosyl]n+1
show the reaction diagram
additional information
?
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Mn2+
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10 mM, 47% of the activity with Mg2+
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
adenosine
Zea saccharata
-
0.7 mM, 30% inhibition
Ammonium molybdate
Zea saccharata
-
7 mM, complete inhibition
AMP
Zea saccharata
-
0.7 mM, 30% inhibition
CaCl2
Zea saccharata
-
0.8 mM, 35% inhibition
Calcium calmodulin
Co2+
-
over 90% inhibition
CoCl2
Zea saccharata
-
4 mM, 70% inhibition
D-glucono-1,5-lactone
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inhibition of glycogen synthase I and II
dADPglucose
Zea saccharata
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1 mM, 30% inhibition
HgCl2
Zea saccharata
-
0.3 mM, complete inhibition
hydroquinone
Zea saccharata
-
5 mM, complete inhibition
methanol
-
-
MgCl2
Zea saccharata
-
-
MnCl2
Zea saccharata
-
7 mM, 30% inhibition
Ni2+
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over 90% inhibition
p-chloromercuribenzoate
pyridoxal-5'-phosphate
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inactivates starch synthase IIa, ADP-glucose protects from inactivation
Zn2+
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over 90% inhibition
ZnSO4
Zea saccharata
-
7 mM, complete inhibition
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1,4-alpha-Glucan branching enzyme
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EC 2.4.1.18, stimulation of unprimed reaction
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ammonium sulfate
amylopectin
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50 mg/ml, 6fold activation of granule-bound starch synthase I
beta-Lactoglobulin
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activation of unprimed reaction
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Bovine plasma albumin
citrate
glutathione
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activation
hemoglobin
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activation of unprimed reaction
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Isopropanol
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above 70%, activation
Myoglobin
-
activation of unprimed reaction
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n-Propanol
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85%, activation
ovomucoid
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activation of unprimed reaction
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potassium acetate
Sodium acetate
succinate
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500 mM, 6fold activation of unprimed starch synthesis
additional information
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peak of activities at the 28th day post anthesis, higher activity in the cultivar with a high starch content
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.1 - 4.08
ADP-glucose
0.000164 - 2.5
ADPglucose
0.75
amylopectin
Zea saccharata
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-
0.000272
dADPglucose
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-
0.000864
glycogen
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Arthrobacter glycogen
0.077
maltose
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0.015 - 16.6
maltotriose
1.1
phytoglycogen
Zea saccharata
-
-
-
2.7
UDPglucose
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-
additional information
additional information
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
235 - 333
ADP-glucose
412
glycogen
Phaseolus vulgaris
A4F2M4
pH 8.0, 30C
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.08
ADP
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-
0.38
D-glucono-1,5-lactone
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.026
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in the presence of 0.5 mg glycogen primer and 500 mM sodium citrate
0.032
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primed reaction, isoenzyme I
0.033
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glycogen synthase I
0.039
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glycogen synthase II
0.06
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unprimed reaction in the presence of 500 mM citrate, recombinant starch synthase I
0.106
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primed reaction, isoenzyme IV
0.118
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primed reaction, isoenzyme III
0.28
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unprimed reaction, isoenzyme III
0.338
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primed reaction, isoenzyme II
1.1
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unprimed reaction, synthase I
2.3
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primed reaction, synthase I
3
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primed reaction
12.2
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primed reaction, recombinant starch synthase I
15.87
-
-
65.47
Zea saccharata
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494
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glycogen synthase I
505
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glcogen synthase II
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7 - 9.5
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7 - 10.3
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starch synthases IIa and Iib, sharp decline in activity below pH 7.0
7
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starch synthase II, 75% of maximal activity at pH 6.5
7.5 - 8.5
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isoenzymes I-IV
8 - 10.3
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starch synthase II, sharp decline in activity below pH 7.0
8
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starch synthase I, 34% of maximal activity at pH 6.5
8.3
Zea saccharata
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-
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6 - 9
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6.5 - 9.7
Zea saccharata
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less than half-maximal activity above and below
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
24 - 30
Zea saccharata
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65% activity at 37C
30
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4 isozymes, primed reaction
40 - 50
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recombinant starch synthase I in the presence of citrate
40
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starch synthase IIb, in the presence of 500 mM citrate
42
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starch synthase I, 15% of maximal activity at 23C
45
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starch synthase IIa, in the presence of 500 mM citrate
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
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activity of starch synthase in the grains follows single-peak curves with the peaks on 24-31 days after pollination. The accumulation rates of starch and its components reach their peaks on 25-32 days after pollination. There is significant positive correlation between adenosine diphosphoglucose diphosphorylase, soluble starch synthase, and starch granule-bound synthase activities
Manually annotated by BRENDA team
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granule-bound starch synthase II
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
PDB
SCOP
CATH
ORGANISM
UNIPROT
Escherichia coli (strain K12)
Escherichia coli (strain K12)
Escherichia coli (strain K12)
Escherichia coli (strain K12)
Escherichia coli (strain K12)
Escherichia coli (strain K12)
Escherichia coli (strain K12)
Pyrococcus abyssi (strain GE5 / Orsay)
Pyrococcus abyssi (strain GE5 / Orsay)
Pyrococcus abyssi (strain GE5 / Orsay)
Pyrococcus abyssi (strain GE5 / Orsay)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
69000
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synthase II, gel filtration
70000
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gel filtration
92700
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sucrose density gradient centrifugation
110000
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synthase I, gel filtration
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
decamer
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10 * 12000, synthase I, SDS-PAGE
hexamer
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6 * 12000, synthase II, SDS-PAGE
oligomer
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enzyme is active in at least 2 oligomeric forms, bands in SDS-PAGE of 11500 Da, 20000 Da, 35000 Da, 50000 Da, 68000 Da, and in gel filtration of 22000 Da and 67000 Da
additional information
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
-
glycogen synthase II, 1.7% carbohydrate may be due to an endogenous primer
proteolytic modification
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
cocrystallization of the inactive glycogen synthase mutant E377A with substrate ADPGlc and cocrystallization of wild-type glycogen synthase with substrate ADPGlc and the glucan acceptor mimic 4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropane)sulfonic acid, i.e. HEPPSO produces a closed form of glycogen synthase and suggests that domain-domain closure accompanies glycogen synthesis. Four bound oligosaccharides are observed, G6a in the interdomain cleft and G6b, G6c, and G6d on the N-terminal domain surface. Extending from the center of the enzyme to the interdomain cleft opening, G6a mostly interacts with the highly conserved N-terminal domain residues lining the cleft of glycogen synthase. The surface-bound oligosaccharides G6c and G6d have less interaction with enzyme and exhibit a more curled, helixlike structural arrangement
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structure of the wild-type enzyme bound to ADP and glucose reveals a 15.2 overall domain-domain closure. The main chain carbonyl group of His-161, Arg-300, and Lys-305 are suggested to act as critical catalytic residues in the transglycosylation. Glu-377 is found on the-face of the glucose and plays an electrostatic role in the active site and as a glucose ring locator. In the mutant E377A-ADP-4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropane)sulfonic acid complex the glucose moiety is either absent or disordered in the active site
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pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.5 - 10
stable
686669
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
15
-
stable at
42
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starch synthase I, no loss of activity after 30 min, starch synthase II, loss of more than 50% activity after 30 min
45
stable below
62
Zea saccharata
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inactivation at
ORGANIC SOLVENT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
more than 70% isopropanol activates, 85% n-propanol activates
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-10C, fraction V, unstable
Zea saccharata
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-15C, fraction IV, 6 months
Zea saccharata
-
-20C, 6 months, 50% loss of activity
-
-20C, at least 4 months, no loss of activity
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-70C, 50 mM Tris/acetate buffer, pH 7.5, 2.5 mM DTT, 10 mM EDTA, 5% w/v sucrose
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-80C, purified His-tagged enzyme, in 20 mM triethanolamine-HCl, pH 8.0, and 20% v/v glycerol, stable for at least 6 months
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-85C, at least 1 year
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0-4C, ammonium sulfate precipitate
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0C, 1 month, 30% loss of activity
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4C, at least 2 weeks, no loss of activity
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addition of 0.04% (w/v) polyvinyl alcohol 50 K and 1 mM dithiothreitol to the glycine buffer, pH 8.4, leads to long-term stability and
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higher yields of both starch synthase and starch branching enzyme, due to activation of inactive enzymes
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
2 isoforms, DEAE-Sepharose, ammonium sulfate, Blue Sepharose, omega-aminobutyl agarose, Mono Q
-
2 isozymes
2 isozymes, DEAE-cellulose, 4-aminobutyl-Sepharose, Bio-Gel P200
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4 isoenzymes, ammonium sulfate, DEAE-cellulose
6 isozymes
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ammonium sulfate, calcium phosphate gel, DEAE-cellulose
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ammonium sulfate, DEAE-cellulose
ammonium sulfate, DEAE-cellulose, ADP-hexanoamine-Sepharose 4B
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ammonium sulfate, DEAE-cellulose, aminobutyl-Sepharose, ADP-hexanolamine-Sepharose, aminopropyl-Sepharose
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ammonium sulfate, maltotriose-Sepharose, DEAE-Toyopearl, Sepharose Cl-6B
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large scale purification from white potato tuber
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partial, from raw strach granules of mature seed
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recombiantly expressed catalytic C-terminal domain (SSIII-CD)
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recombinant enzyme
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recombinant N-terminally His-tagged GSase from Escherichia coli strain BL21(DE3) or Top10 by nickel affinity chromatography and dialysis
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recombinant starch synthase I, ammonium sulfate, amylose column, Mono Q
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starch synthase III, ammonium sulfate, DEAE-Sepharose, Blue Sepharose, Mono Q, cyclohexaamylose
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starch synthases I and II, Q-Sepharose, Mono Q, amylose-agarose
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wild-type and mutant enzymes expressed in Escherichia coli
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
cloning and sequencing of cDNA encoding SSIIa of japonica and indica rice cultivars, expression in Escherichia coli
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cloning of starch synthase III cDNA
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construction of recombinant full length and truncated isoforms of SSIII, lacking one, two, or three starch-binding domains, and recombinant proteins, containing three, two, or one starch-binding domains, to investigate the role of these domains in enzyme activity
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expression in Escherichia coli
expression of C-terminal domain in Escherichia coli
expression of full length and truncated starch synthase IIa and IIb in Escherichia coli
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expression of full-length and truncated enzyme in Escherichia coli
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expression of granule-bound starch synthase I and soluble starch synthase II in Escherichia coli
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expression of granule-bound starch synthase I in Escherichia coli
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expression of granule-bound starch synthase in Escherichia coli
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expression of N-terminally His-tagged GSase in Escherichia coli strain BL21(DE3) or Top10
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expression of OsSSIII-1 in Escherichia coli; expression of OsSSIII-2 in Escherichia coli; expression of OsSSIV-1 in Escherichia coli; expression of OsSSIV-2 in Escherichia coli
expression of PvSSI and PvSSII-1 in Escherichia coli
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expression of starch synthase II in Escherichia coli and potato
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the catalytic C-terminal domain (SSIII-CD) of is cloned and expressed in Escherichia coli. SSIII-CD fully complements the production of glycogen by an Agrobacterium tumefaciens glycogen synthase null mutant, suggesting that this truncated isoform restores in vivo de novo synthesis of bacterial glycogen
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three recombinant proteins are constructed: putative mature recombinant SSIII (rPvSSII), recombinant kidney bean SSIII N-domain (rPvSSIII-N), and recombinant kidney bean SSIII C-domain (rPvSSIII-C)
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
expression reaches maximum level at the middle developmental age of endosperm after pollination
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
W366A
-
mutation in starch-binding domains, 3fold decrease in affinity to starch
W366A/Y394A
-
mutation in starch-binding domains, significant decrease in affinity to starch
Y394A
-
mutation in starch-binding domains, 2fold decrease in affinity to starch
C7S/C409S
-
exhibits comparable specific activity and apparent affinity for ADP-Glc to wild-type. Use as alternative in crystallization trials to avoid aggregation
K193E
-
mutation does not alter the binding of ADP-glucose, Km-value for amylopectin is 3.6fold higher than the wild-type value, KM-value for glycogen is 3.2fold lower than the wild-type value
K193Q
-
mutation does not alter the binding of ADP-glucose, Km-value for amylopectin is 1.5fold lower than the wild-type value, KM-value for glycogen is 15.5fold lower than the wild-type value
K193R
-
mutation does not alter the binding of ADP-glucose, Km-value for amylopectin is 2.6fold higher than the wild-type value, KM-value for glycogen is 2.5fold lower than the wild-type value
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
agriculture
nutrition
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analysis of the natural variations of isoforms granule-bound starch synthase GBSSI, starch synthases SSI and SSIIa and their effect on starch properties and eating quality of rice. Rice with the combinantion of the Wx allele for GBSSI and the alk allele for SSIIa has soft and sticky texture both after cooking and after storage. Variation of SSI alleles hardly affects the eating quality
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