Information on EC 2.4.1.46 - monogalactosyldiacylglycerol synthase

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

EC NUMBER
COMMENTARY hide
2.4.1.46
-
RECOMMENDED NAME
GeneOntology No.
monogalactosyldiacylglycerol synthase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
UDP-alpha-D-galactose + a 1,2-diacyl-sn-glycerol = UDP + a 1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol
show the reaction diagram
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-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hexosyl group transfer
-
-
-
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
galactolipid biosynthesis I
-
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Glycerolipid metabolism
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Metabolic pathways
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SYSTEMATIC NAME
IUBMB Comments
UDP-galactose:1,2-diacyl-sn-glycerol 3-beta-D-galactosyltransferase
This enzyme adds only one galactosyl group to the diacylglycerol; EC 2.4.1.241, digalactosyldiacylglycerol synthase, adds a galactosyl group to the product of the above reaction. There are three isoforms in Arabidopsis that can be divided into two types, A-type (MGD1) and B-type (MGD2 and MGD3). MGD1 is the isoform responsible for the bulk of monogalactosyldiacylglycerol (MGDG) synthesis in Arabidopsis [4].
CAS REGISTRY NUMBER
COMMENTARY hide
37277-55-7
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
type B, atMGD2
-
-
Manually annotated by BRENDA team
var. pennsylvanicus
-
-
Manually annotated by BRENDA team
putative
UniProt
Manually annotated by BRENDA team
Cucumis sp.
-
-
-
Manually annotated by BRENDA team
maximal activity in 14-18 days old rats
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-
Manually annotated by BRENDA team
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UniProt
Manually annotated by BRENDA team
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
UDP-galactose + 1,2-diacyl-sn-glycerol
UDP + 3-beta-D-galactosyl-1,2-diacyl-sn-glycerol
show the reaction diagram
UDP-galactose + 1,2-diacylglycerol
UDP + 3-beta-D-galactosyl-1,2-diacyl-sn-glycerol
show the reaction diagram
-
-
-
-
?
UDP-galactose + 1,2-diacylglycerol
UDP + 3-beta-D-galactosyl-1,2-diacylglycerol
show the reaction diagram
UDP-galactose + 1,2-dicaproylglycerol
UDP + 3-beta-D-galactosyl-1,2-dicaproylglycerol
show the reaction diagram
-
-
-
?
UDP-galactose + 1,2-didecanoylglycerol
UDP + 3-beta-D-galactosyl-1,2-didecanoylglycerol
show the reaction diagram
-
-
-
?
UDP-galactose + 1,2-dilauroylglycerol
UDP + 3-beta-D-galactosyl-1,2-dilauroylglycerol
show the reaction diagram
-
-
-
?
UDP-galactose + 1,2-dilinoleoylglycerol
UDP + 3-beta-D-galactosyl-1,2-dilinoleoylglycerol
show the reaction diagram
UDP-galactose + 1,2-dioleoylglycerol
UDP + 3-beta-D-galactosyl-1,2-dioleoylglycerol
show the reaction diagram
UDP-galactose + 1,2-dipalmitoylglycerol
UDP + 3-beta-D-galactosyl-1,2-dipalmitoylglycerol
show the reaction diagram
UDP-galactose + 1,2-distearoylglycerol
UDP + 3-beta-D-galactosyl-1,2-distearoylglycerol
show the reaction diagram
UDP-galactose + 1,2-myristoylglycerol
UDP + 3-beta-D-galactosyl-1,2-myristoylglycerol
show the reaction diagram
-
-
-
?
UDP-galactose + sn-1,2-dioleoylglycerol
UDP + 3-beta-D-galactosyl-1,2-dioleoyl-sn-glycerol
show the reaction diagram
-
-
-
?
UDP-galactose + sn-1-oleoyl-sn-2-palmitoyl-glycerol
UDP + 3-beta-D-galactosyl-sn-1-oleoyl-sn-2-palmitoyl-glycerol
show the reaction diagram
-
-
-
?
UDPgalactose + 1,2-diacylglycerol
UDP + 3-beta-D-galactosyl-1,2-diacylglycerol
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
UDP-galactose + 1,2-diacyl-sn-glycerol
UDP + 3-beta-D-galactosyl-1,2-diacyl-sn-glycerol
show the reaction diagram
UDPgalactose + 1,2-diacylglycerol
UDP + 3-beta-D-galactosyl-1,2-diacylglycerol
show the reaction diagram
additional information
?
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Ca2+
-
addition of cation stimulates, efficiency in descending order: Mn2+, Co2+, Mg2+, Fe2+, Ca2+, Ni2+, K+, Na+
Co2+
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addition of cation stimulates, efficiency in descending order: Mn2+, Co2+, Mg2+, Fe2+, Ca2+, Ni2+, K+, Na+
Fe2+
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addition of cation stimulates, order of efficiency in descending order: Mn2+, Co2+, Mg2+, Fe2+, Ca2+, Ni2+, K+, Na+
K+
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addition of cation stimulates, efficiency in descending order: Mn2+, Co2+, Mg2+, Fe2+, Ca2+, Ni2+, K+, Na+
Na+
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addition of cation stimulates, efficiency in descending order: Mn2+, Co2+, Mg2+, Fe2+, Ca2+, Ni2+, K+, Na+
Ni2+
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addition of cation stimulates, efficiency in descending order: Mn2+, Co2+, Mg2+, Fe2+, Ca2+, Ni2+, K+, Na+
Zn2+
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1 mM, stimulation, inhibition at 10 mM
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
4-hydroxymercuribenzoic acid
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0.01 mM, 65% inhibition
citraconic anhydride
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0.01 and 0.05 mM, 47% and 97% inactivation after 30 min, respectively
Cu2+
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25 mM, complete inhibition
galvestine-1
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competitive to diacylglycerol
galvestine-2
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N-ethylmaleimide
o-phenanthroline
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0.1 mM, 55% inhibition, 1,2-dioleoylglycerol protects and activates enzyme
oleic acid
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0.3 mM, 58% inhibition
tert-butyoxycarbonyl-L-methionine hydrosuccinimidyl ester
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0.2 mM, almost complete inactivation after 30 min
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
illumination
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3fold increase of activity in dark-grown seedlings 42 h after illumination
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Lipid
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addition of lipids extracted from chloroplast membranes is necessary to reveal activity of highly delipidated enzyme fraction
myristic acid
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stimulates
palmitic acid
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stimulates
phosphatidic acid
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allosterically activates MGD1, half-maximal activation at about 0.2 mol%. With 0.15 mol% of phosphatidic acid, the enzyme velocity versus substrate curve is sigmoid, whereas with 1.5 mol% of phosphatidic acid, the curve is hyperbolic. MGDG synthase activity of leaf homogenates is dependent on the constant presence of phosphatidic acid, decrease of phosphatidic acid production leads to a decrease of the MGDG synthase activity. Molecular discrimination of phosphatidic acid and phosphatidylglycerol binding sites, overview
phosphatidylglycerol
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best activator of partially purified, delipidated enzyme
phosphatidylinositol
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activation of partially purified, delipidated enzyme
SDS
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stimulates
sulfolipid
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activation of partially purified, delipidated enzyme
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additional information
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1
diacylglycerol
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-
0.0022
dilinoleoylglycerol
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in envelope membrane vesicles
0.02 - 0.18
dioleoylglycerol
0.0183
UDP-galactose
pH 7.8, 30°C
0.04 - 0.1
UDPgalactose
additional information
additional information
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.008 - 0.052
UDP
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.01
galvestine-1
Arabidopsis thaliana
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pH 7.8, temperature not specified in the publication
0.012
galvestine-2
Arabidopsis thaliana
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pH 7.8, temperature not specified in the publication
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.0531
purified His tagged protein, not significantly influenced by phosphatidic acid, pH 7.8, 30°C
2.2 - 3.2
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7.04
membrane fraction of mgdA expressing Escherichia coli, not significantly influenced by phosphatidic acid, pH 7.8, 30°C
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7
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approx. value
7.5 - 8.5
recombinant isoenzyme MGD A
7.8
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assay at
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.5 - 9
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55% of maximal activity at pH 5.5, 85% of maximal activity at pH 9.0
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
30
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assay at, activity maximum in long-term incubation
50
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activity maximum in short-term incubation
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
high expression of atMGD1::GUS is detected in all green tissues
Manually annotated by BRENDA team
isozyme MGD2; isozyme MGD3
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
-
membrane-bound
Manually annotated by BRENDA team
additional information
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import of pMGD1 is reduced by thermolysin pretreatment of chloroplasts
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Manually annotated by BRENDA team
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
22000
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gel filtration
97000
inactivation after gamma-ray irradiation
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
monomer
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1 * 22000, SDS-PAGE
additional information
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the structure model for an MGD monomer comprises 2 Rossman domains, C- and N-domains
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
dithiothreitol is essential to prevent loss of activity during purification
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
cholate-solubilization, gel filtration, Zn2+-Sepharose affinity chromatography
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hydroxyapatite, partial purification
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immobilized metal ion affinity chromatography
native isozyme from chloroplast envelope membranes from leaf samples; native isozyme from chloroplast envelope membranes from leaf samples; native isozyme from chloroplast envelope membranes from leaf samples
native isozymes from chloroplast envelope membranes from leaf samples
Cucumis sp.
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recombinant wild-type and mutant C-terminally His6-tagged MGD1 from Escherichia coli by nickel affinity chromatography and gel filtration
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in Escherichia coli BL21
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expression in Escherichia coli; expression in Escherichia coli; expression in Escherichia coli
expression of isoenzyme MGD A in Escherichia coli
expression of wild-type and mutant C-terminally His6-tagged MGD1 in Escherichia coli
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His tagged protein expressed in Escherichia coli BL21(DE3), expressed in Arabidopsis thaliana
overexpressed in Escherichia coli
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
cytokinins strongly suppress MGD2 expression in the root, regulation, overview; cytokinins strongly suppress MGD3 expression in the root, regulation, overview
expression of MGD2 is induced by phosphate starvation and hydrogen peroxide treatment. Auxin is required for the Pi starvation-induced expression of MGD2, regulation, overview; expression of MGD3 is induced by phosphate starvation and hydrogen peroxide treatment. Auxin is required for the Pi starvation-induced expression of MGD3, regulation, overview; MGD1 expression is induced by light and cytokinin treatment
in cucumber seedlings, MGDG synthase activity is strongly increased by treatment with greening-promoting factors such as light and cytokinins
Cucumis sp.
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mgd1-1 knockdown does not affect targeting of chloroplast proteins, but increases the photoactive to photoinactive protochlorophyllide ratio, and photoprotective responses are induced. Mutant mgd1-1 cannot withstand high light intensities, apparently due to impairment of another photoprotective mechanism, the xanthophyll cycle, mediated by increased conductivity of the thylakoid membrane leading to a higher pH in the thylakoid interior, which impairs the pH-dependent activation of violaxanthin de-epoxidase and PsbS, phenotype, overview
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D150N
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the mutant shows enhanced activation by phosphatidylglycerol binding, but unaltered activation by phosphatidic acid compared to the wild-type enzyme
P189A
-
the mutant shows wild-type catalytic capability, but modified phosphatidylglycerol binding capability compared to the wild-type enzyme
R260A
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the mutant shows enhanced activation by phosphatidylglycerol binding, but unaltered activation by phosphatidic acid compared to the wild-type enzyme
W287A
-
the mutant shows wild-type catalytic capability, but modified phosphatidylglycerol binding capability compared to the wild-type enzyme
G430C
naturally occuring mutation, Gly is invariant in vascular plants
G94D
naturally occuring mutation
M144V
naturally occuring mutation, invariant residue, essential for function
additional information