Information on EC 2.4.1.82 - galactinol-sucrose galactosyltransferase

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The expected taxonomic range for this enzyme is: Magnoliophyta

EC NUMBER
COMMENTARY
2.4.1.82
-
RECOMMENDED NAME
GeneOntology No.
galactinol-sucrose galactosyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
alpha-D-galactosyl-(1->3)-1D-myo-inositol + sucrose = myo-inositol + raffinose
show the reaction diagram
ping-pong reaction mechanism
Q8VWN6
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
hexosyl group transfer
-
-
-
-
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Galactose metabolism
-
-
lychnose and isolychnose biosynthesis
-
-
stachyose biosynthesis
-
-
stellariose and mediose biosynthesis
-
-
SYSTEMATIC NAME
IUBMB Comments
alpha-D-galactosyl-(1->3)-1D-myo-inositol:sucrose 6-alpha-D-galactosyltransferase
4-Nitrophenyl alpha-D-galactopyranoside can also act as donor. The enzyme also catalyses an exchange reaction between raffinose and sucrose (cf. EC 2.4.1.123, inositol 3-alpha-galactosyltransferase).
SYNONYMS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
galactosyltransferase, galactinol-sucrose
-
-
-
-
CAS REGISTRY NUMBER
COMMENTARY
62213-45-0
-
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
; plants are cold-treated
-
-
Manually annotated by BRENDA team
; plants are cold-treated
-
-
Manually annotated by BRENDA team
heat shock transcription factor A2 HsfA2 overexpressing plants
-
-
Manually annotated by BRENDA team
heat shock transcription factor A2 HsfA2 overexpressing plants
UniProt
Manually annotated by BRENDA team
cultivar Guonong No. 25
UniProt
Manually annotated by BRENDA team
v. Hudson
-
-
Manually annotated by BRENDA team
L. cv. Bravo
-
-
Manually annotated by BRENDA team
v. California Dark Red
-
-
Manually annotated by BRENDA team
cv. Wunder von Kelvedon
SwissProt
Manually annotated by BRENDA team
; plants are cold-treated
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
physiological function
-
enzyme is involved in stress resistance
physiological function
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
raffinose synthase 2 plays a role in heat shock reaction and protection from oxidative stress
physiological function
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
raffinose synthase 4 plays a role in protection from oxidative stress
physiological function
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
raffinose synthase 5 plays a role in protection from oxidative stress
physiological function
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
raffinose synthase 6 plays a role in protection from oxidative stress
physiological function
Q6ZLJ9
raffinose synthase catalyzes the transfer of galactosyl residue from galactinol to sucrose to form raffinose
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
1-alpha-D-galactosyl-myo-inositol + D-ononitol
myo-inositol + alpha-D-galactosyl-D-ononitol
show the reaction diagram
Q8VWN6
D-ononitol is 1-D-4-O-methyl-myo-inositol
-
r
1-alpha-D-galactosyl-myo-inositol + D-pinitol
myo-inositol + galactopinitol A
show the reaction diagram
Q8VWN6
D-pinitol is 1-D-3-O-methyl-chiro-inositol
i.e. O-alpha-D-galactopyranosyl-(1,2)-4-O-methyl-D-chiro-inositol
r
1-alpha-D-galactosyl-myo-inositol + H2O
myo-inositol + D-galactose
show the reaction diagram
-
hydrolysis, in the absence of acceptor substrate
-
-
?
1-alpha-D-galactosyl-myo-inositol + H2O
myo-inositol + D-galactose
show the reaction diagram
Q8VWN6
hydrolysis, in the absence of acceptor substrate
-
-
?
1-alpha-D-galactosyl-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
-
-
-
r
1-alpha-D-galactosyl-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
-
-
-
r
1-alpha-D-galactosyl-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
-
-
-
r
1-alpha-D-galactosyl-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
Q8VWN6
-
-
r
1-alpha-D-galactosyl-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
-
first step in biosynthesis of raffinose sugars
-
-
-
4-nitrophenol-alpha-D-galactopyranoside + sucrose
4-nitrophenol + raffinose
show the reaction diagram
-
-
-
-
?
4-nitrophenol-alpha-D-galactopyranoside + sucrose
4-nitrophenol + raffinose
show the reaction diagram
Q8VWN6
-
-
-
?
alpha-D-galactosyl-(1->3)-1D-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
Q6ZLJ9
-
-
-
?
alpha-D-galactosyl-D-ononitol + sucrose
D-ononitol + raffinose
show the reaction diagram
Q8VWN6
-
-
?
galactinol + sucrose
myo-inositol + raffinose
show the reaction diagram
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
-
-
-
ir
myo-inositol + raffinose
1-alpha-D-galactosyl-1D-myo-inositol + sucrose
show the reaction diagram
-
-
-
-
r
raffinose + sucrose
sucrose + raffinose
show the reaction diagram
-
exchange reaction
-
r
raffinose + sucrose
sucrose + raffinose
show the reaction diagram
-
exchange reaction
-
r
raffinose + sucrose
sucrose + raffinose
show the reaction diagram
-
exchange reaction
-
r
galactinol + sucrose
raffinose + ?
show the reaction diagram
B5G4T9
-
-
-
?
additional information
?
-
Q8VWN6
substrate specificity
-
-
-
additional information
?
-
-
UDP-galactose is no substrate
-
-
-
additional information
?
-
Q8VWN6
raffinose is no acceptor substrate
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
1-alpha-D-galactosyl-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
-
first step in biosynthesis of raffinose sugars
-
-
-
alpha-D-galactosyl-(1->3)-1D-myo-inositol + sucrose
myo-inositol + raffinose
show the reaction diagram
Q6ZLJ9
-
-
-
?
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
1-deoxygalactonojirimycin
Q8VWN6
strong, competitive towards galactinol
Ag+
-
1 mM, strong
Al3+
-
1 mM, strong
Hg2+
-
1 mM, strong
iodoacetamide
-
49% inhibition at 1 mM
Mn2+
-
-
myo-Inositol
Q8VWN6
competitive against sucrose
N-ethylmaleimide
-
90% inhibition at 1 mM
Ni2+
Q8VWN6
destabilization, 30.2% activity at 1 mM
Sucrose
Q8VWN6
-
Zn2+
-
1 mM, strong
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
heat shock transcription factor A2
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
in HsfA2 overexpressing plants transcription levels of RS2 increases 5fold
-
additional information
Q84VX0, Q8RX87, Q94A08, Q9FND9, Q9SYJ4
50 microM methylviologen, an enhancer of oxidative stress, increases transcription levels of RS2 5fold after 6 hours; 50 microM methylviologen, an enhancer of oxidative stress, increases transcription levels of RS4 3fold after 3 and 6 hours; 50 microM methylviologen, an enhancer of oxidative stress, increases transcription levels of RS5 twice after 6 hours; 50 microM methylviologen, an enhancer of oxidative stress, increases transcription levels of RS6 4fold after 3 hours and 6fold after 6 hours
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
1
galactinol
Q8VWN6
hydrolysis
7
galactinol
-
+ sucrose
7.3
galactinol
Q8VWN6
partially purified native enzyme, raffinose synthesis
7.9
galactinol
Q8VWN6
recombinant enzyme in Sf21 cell extract, raffinose synthesis
10
raffinose
-
+ sucrose, exchange reaction
1
Sucrose
-
cosubstrate galactinol
2.9
Sucrose
-
+ raffinose, exchange reaction
22.6
Sucrose
Q8VWN6
recombinant enzyme in Sf21 cell extract, raffinose synthesis
22.9
Sucrose
Q8VWN6
partially purified native enzyme, raffinose synthesis
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.189
1-deoxygalactonojirimycin
Q8VWN6
-
10.1
myo-Inositol
Q8VWN6
competitive against sucrose
22.3
myo-Inositol
Q8VWN6
noncompetitive against galactinol
3.7
Sucrose
Q8VWN6
hydrolysis reaction of galactinol, noncompetitive against galactinol
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
0.00005
Q8VWN6
recombinant in Sf21 insect cells
0.0012
-
crude seed extract
0.00138
-
protoplast
0.00258
-
protoplast
0.00396
-
protoplast
0.045
-
-
0.045
-
partially purified enzyme
0.497
-
purified enzyme
additional information
-
no enzyme activity is found in chloroplasts
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
6 - 7
-
-
6.5
-
assay at, RafS enzyme activity shows neutral pH optima, corresponding to the pH of the cytosol
7 - 8
-
exchange reaction
7
Q8VWN6
-
pH RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
5.7 - 7.8
-
about half-maximal activity at pH 5.7 and pH 7.8
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
30
Q8VWN6
assay at
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
28 - 50
-
about half-maximal activity at 28C and 50C
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
-
bases, sheath, blade. Drough stress does not increase activity
Manually annotated by BRENDA team
B5G4T9
highest expression in leaves
Manually annotated by BRENDA team
-
developing
Manually annotated by BRENDA team
Q8VWN6
maturing
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
80000
-
gel filtration
638269
88700
Q8VWN6
amino acid sequence determination
638271
100000
-
glycerol density gradient centrifugation
638269
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
?
B5G4T9
x * 79000, calculated from amino acid sequence
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
50
-
10 min, 80% loss of activity, galactinol and raffinose protect, not sucrose
638269
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
dithioerythritol stabilizes during purification
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
4C, in crude extract, t1/2: 3 days
-
frozen, purified enzyme, at least 1 month
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
partial
-
no success in purifying the recombinant His-tagged enzyme from Sf21 insect cells; partial
Q8VWN6
partial
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in Nicotiana tabacum cultivar Yunyan 85
B5G4T9
functional expression as His-tagged protein in Spodoptera frugiperda Sf21 cells via baculovirus infection
Q8VWN6
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
enzyme expression can be induced by low temperature (highest expression after 2 h at 6C) and 0.15 mM (fruit) and 0.2 mM (leaf) abscisic acid
B5G4T9
gene expression of Os07g0209100 encoding raffinose synthase is upregulated by overexpression of the transcription factor 11 (WRKY11) induced by heat pretreatment
Q6ZLJ9
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
S150F
B2ZF64
line 165, mutation induced by mutagen ethyl-methanesulfonate, seed phenotype does not differ from wild-type
T107I
B2ZF64
line 397, mutation induced by mutagen ethyl-methanesulfonate, seed sucrose is increased by 28%, raffinose is reduced to 37% and stachyose is reduced to approximately 24% compared to wild-type