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Literature summary for 2.4.1.91 extracted from

  • Owens, D.K.; McIntosh, C.A.
    Identification, recombinant expression, and biochemical characterization of a flavonol 3-O-glucosyltransferase clone from Citrus paradisi (2009), Phytochemistry, 70, 1382-1391.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expressed in Escherichia coli BL21(DE3)RIL cells Citrus x paradisi

General Stability

General Stability Organism
activities recorded in phosphate, MOPS, and bicine buffers are not significantly different, but assays in Tris buffer result in a reduction of enzyme activity by 51% under optimal pH conditions Citrus x paradisi

Inhibitors

Inhibitors Comment Organism Structure
2,3-Butanedione 46% residual activity at 10 mM Citrus x paradisi
Cu2+ 0.03% residual activity at 10 mM Citrus x paradisi
Fe2+ 0.09% residual activity at 10 mM Citrus x paradisi
additional information L-cysteine, L-histidine, L-arginine, L-tryptophan, and L-tyrosine residues are important for activity; not inhibited by succinic anhydride, K+, Na+, Ca2+,Mg2+, and Mn2+ Citrus x paradisi
N-bromo-succinimide 17% residual activity at 10 mM Citrus x paradisi
Tetranitromethane 13% residual activity at 10 mM Citrus x paradisi
Tris Tris inhibits flavonol 3-O-GT as activity levels are significantly lower than corresponding buffers across its entire buffer range Citrus x paradisi
UDP 6% residual activity at 10 mM Citrus x paradisi
Zn2+ 26% residual activity at 10 mM Citrus x paradisi

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.012
-
kaempferol apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
0.033
-
myricetin apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
0.067
-
quercetin apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
0.669
-
UDP-glucose apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ 119% relative activity at 1 mM Citrus x paradisi
Na2SO4 118% relative activity at 1 mM Citrus x paradisi
Succinic anhydride 115% relative activity at 1 mM Citrus x paradisi

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
51000
-
SDS-PAGE Citrus x paradisi
51200
-
calculated from amino acid sequence Citrus x paradisi

Organism

Organism UniProt Comment Textmining
Citrus x paradisi C5MR71
-
-

Purification (Commentary)

Purification (Comment) Organism
TALON metal affinity resin column chromatography, gel filtration Citrus x paradisi

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information does not glucosylate naringenin, apigenin, luteolin, dihydroquercetin, 4'-acetoxy-7-hydroxy-6-methoxy-isoflavone, 4'-methoxy-flavonol, 3',4'-dimethoxy-flavonol, anthocyanidin, and cyanidin Citrus x paradisi ?
-
?
UDP-alpha-D-glucose + kaempferol 57.9% activity compared to quercetin, glucosylation occurs at the 3 hydroxyl position Citrus x paradisi UDP + kaempferol 3-O-beta-D-glucoside
-
?
UDP-alpha-D-glucose + quercetin 100% activity, glucosylation occurs at the 3 hydroxyl position Citrus x paradisi UDP + quercetin 3-O-beta-D-glucoside
-
ir
UDP-glucose + myricetin 40.7% activity compared to quercetin, glucosylation occurs at the 3 hydroxyl position Citrus x paradisi UDP + myricetin 3-O-beta-D-glucoside
-
?

Synonyms

Synonyms Comment Organism
flavonol 3-O-glucosyltransferase
-
Citrus x paradisi
flavonol 3-O-GT
-
Citrus x paradisi

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
40 50
-
Citrus x paradisi

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
40 60 the enzyme is stable when preincubated for up to 10 min at 40°C with a significant decrease in activity at 50°C and an almost complete loss of detectable activity at 60°C and beyond Citrus x paradisi

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.5955
-
kaempferol apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
0.6252
-
myricetin apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
1.047
-
quercetin apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
1.442
-
UDP-glucose apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
-
the optimum pH is 7.5 with a pronounced buffer effect noted for reactions performed in Tris-HCl buffer Citrus x paradisi

pH Stability

pH Stability pH Stability Maximum Comment Organism
5.5 8.5 reduction to 59% maximal activity at pH 5.5 and 57% at pH 8.5 Citrus x paradisi

pI Value

Organism Comment pI Value Maximum pI Value
Citrus x paradisi calculated from amino acid sequence
-
6.3

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
2.2
-
UDP-glucose apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
15.6
-
quercetin apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
18.9
-
myricetin apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi
49.6
-
kaempferol apparent value, in 50 mM phosphate buffer (pH 7.5), at 40°C Citrus x paradisi