Ligand beta-lactose

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Basic Ligand Information

Molecular Structure
Picture of beta-lactose (click for magnification)
Molecular Formula
BRENDA Name
InChIKey
C12H22O11
beta-lactose
GUBGYTABKSRVRQ-DCSYEGIMSA-N
Synonyms:
(+)-lactose, 4-O-beta-D-galactopyranosyl-beta-D-glucopyranose, 4-O-beta-D-galactopyranosyl-D-glucopyranoside, 4-O-beta-D-galactopyranosyl-D-glucose, 4-O-beta-D-galactopyranosyl-glucopyranoside, 4-O-beta-D-galactosyl-beta-D-glucose, beta-D-Gal(1-4)-D-Glc, beta-D-Gal-(1-->4)-D-Glc, beta-D-Gal-(1->4)-D-Glc, beta-D-galactosyl-(1->4)-D-glucose, beta-D-galactosyl-1,4-D-glucose, beta-D-lactose, D-(+)-lactose, D-Gal-beta-(1->4)-D-Glc, D-galactosyl-1,4-beta-D-glucose, D-Galbeta(1,4)-D-Glc, D-lactose, Gal-beta-(1-4)-Glc, Gal-beta-1,4-Glc, Galbeta(1,4)-Glc, Galbeta(1,4)Glc, Galbeta(1-4)Glc, Galbeta1-4Glc, lactobiose, lactose, lactose[side 1]

Show all pahtways known for Show all pathways known for beta-lactose

Roles as Enzyme Ligand

In Vivo Substrate in Enzyme-catalyzed Reactions (28 results)

EC NUMBER
PROVEN IN VIVO REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
beta-D-lactose + O2 = beta-D-lacto-hexodialdose + H2O2
show the reaction diagram
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lactose + oxidized 2,6-dichlorophenolindophenol = lactono-1,5-lactone + reduced 2,6-dichlorophenolindophenol
show the reaction diagram
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sucrose + lactose = D-glucose + O-beta-D-galactopyranosyl-(1,4)-O-beta-D-glucopyranosyl-(1,2)-beta-D-fructofuranoside
show the reaction diagram
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GDP-fucose + Galbeta1-4Glc = Fucalpha1-2Galbeta1-4Glc + GDP
show the reaction diagram
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[protein]-Npi-phospho-L-histidine + lactose[side 1] = [protein]-L-histidine + lactose 6'-phosphate[side 2]
show the reaction diagram
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4-O-beta-D-galactopyranosyl-D-glucopyranoside + H2O = D-galactose + beta-D-glucose
show the reaction diagram
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lactose + H2O = D-glucose + D-galactose
show the reaction diagram
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In Vivo Product in Enzyme-catalyzed Reactions (14 results)

EC NUMBER
PROVEN IN VIVO REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
2'-fucosyllactose + H2O = L-fucose + lactose
show the reaction diagram
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-

Substrate in Enzyme-catalyzed Reactions (231 results)

EC NUMBER
REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
lactose + NAD+ = ? + NADH + H+
show the reaction diagram
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lactose + O2 = 2-dehydrolactose + H2O2
show the reaction diagram
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D-lactose + 2,6-dichlorophenolindophenol = D-lactono-1,5-lactone + reduced 2,6-dichlorophenolindophenol
show the reaction diagram
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acetyl-CoA + lactose = CoA + 4-O-(6-O-acetyl-beta-D-galactopyranosyl)-beta-D-glucopyranose
show the reaction diagram
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UDP-N-acetylglucosamine + lactose = UDP + GlcNAcbeta(1-3)Galbeta(1-4)Glc
show the reaction diagram
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UDP-glucose + lactose = UDP + ?
show the reaction diagram
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UDP-N-acetyl-D-glucosamine + lactose = UDP + GlcNAcbeta(1-6)Galbeta(1-4)Glc
show the reaction diagram
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UDP-galactose + D-galactosyl-1,4-beta-D-glucose = UDP + D-galactosyl-1,3-beta-D-galactosyl-1,4-beta-D-glucose
show the reaction diagram
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lactose + phosphate = alpha-D-galactose 1-phosphate + D-glucose
show the reaction diagram
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UDP-galactose + lactose = ?
show the reaction diagram
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UDP-galactose + lactose = UDP + beta-D-galactosyl-lactose
show the reaction diagram
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UDP-N-acetyl-D-glucosamine + lactose = UDP + N-acetyl-D-glucosaminyllactose
show the reaction diagram
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sucrose + lactose = ?
show the reaction diagram
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CMP-N-acetylneuraminate + lactose = CMP + 6'-sialyllactose
show the reaction diagram
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CMP-N-acetylneuraminate + lactose = CMP + ?
show the reaction diagram
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[protein]-Npi-phospho-L-histidine + lactose[side 1] = [protein]-L-histidine + lactose 6'-phosphate[side 2]
show the reaction diagram
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Galbeta1-3GlcNAcbeta-p-nitrophenol + lactose = Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc + ?
show the reaction diagram
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sucrose + lactose = lactosucrose
show the reaction diagram
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4-O-beta-D-galactopyranosyl-D-glucose + H2O = beta-D-galactose + D-glucose
show the reaction diagram
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beta-L-fucosyl fluoride + lactose + H2O = ?
show the reaction diagram
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lactose + H2O = ?
show the reaction diagram
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lactose + H2O = D-glucose
show the reaction diagram
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lactose + H2O = D-glucose + D-galactose
show the reaction diagram
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beta-Lactose = alpha-Lactose
show the reaction diagram
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Product in Enzyme-catalyzed Reactions (126 results)

EC NUMBER
REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
D-glucose + alpha-D-galactose 1-phosphate = beta-D-galactosyl-(1->4)-D-glucose + phosphate
show the reaction diagram
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L-Fuc-alpha-(1->3)-[D-Gal-beta-(1->4)]-D-Glc + H2O = L-fucose + D-Gal-beta-(1->4)-D-Glc
show the reaction diagram
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p-nitrophenyl-beta-D-galactoside + D-glucose = lactose + p-nitrophenol
show the reaction diagram
lactosylsphingosine + H2O = lactose + sphingosine
show the reaction diagram
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4-methylumbelliferyl-beta-D-lactoside + H2O = 4-methylumbelliferone + D-lactose
show the reaction diagram
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alpha-lactose = beta-lactose
show the reaction diagram
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Activator in Enzyme-catalyzed Reactions (9 results)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE
UDP-GlcDH activities in extracts of Lactococcus lactis strain NFHA01 induced with both 0.5% and 2% lactose are significantly higher than that of the same strain without induction. UDP-GlcDH activity of NFHA01 induced with 2% lactose is about 110% higher than that of 0.5% lactose induction
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favores CGTase synthesis
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50% activation at 1%, with concentration of 1% sucrose
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uncompetitive activator
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71% activation at 3 mM
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induces enzyme activity
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Inhibitor in Enzyme-catalyzed Reactions (51 results)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE
24.5% inhibition of recombinant GlcAT-S at 5 mM, no inhibition of recombinant GlcAT-P
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competitive with antifreeze glycoprotein
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inhibits recombinant CelS activity on cellopentaose, 81% inhibition at 20 mg/ml lactose
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10 mM, 68% inhibition. Inhibitory effect is abolished by Ca2+
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51000 Da subunit from the multicomponent cellulase complexes
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competitive to pyridoxine-5'-beta-D-glucoside
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10 mM, 27% inhibition
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o-nitrophenyl-beta-D-galactoside hydrolyzing activity
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0.1 M, 41% inhibition of beta-galactoside hydrolysis, 18% inhibition of beta-glucoside hydrolysis
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inhibition of pyridoxine-5'-beta-D-glucoside hydrolase activity, competitive
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3D Structure of Enzyme-Ligand-Complex (PDB) (18 results)

Enzyme Kinetic Parameters

kcat Value (Turnover Number) (179 results)

EC NUMBER
TURNOVER NUMBER [1/S]
TURNOVER NUMBER MAXIMUM [1/S]
COMMENTARY
LITERATURE
9.23
-
-
33.8
-
pH 6, 37°C
1500
-
release of D-glucose, pH 7.5, 80°C
47
-
pH 6.0, 37°C

KM Value (370 results)

EC NUMBER
KM VALUE [MM]
KM VALUE MAXIMUM [MM]
COMMENTARY
LITERATURE
781
-
-
1.7
-
-
1.7
-
-
0.5
-
-
475
-
-

Ki Value (16 results)

EC NUMBER
KI VALUE [MM]
KI VALUE MAXIMUM [MM]
COMMENTARY
LITERATURE
61
-
pH 7.0, 20°C
14.5
-
-
56
-
pH 6.0, 37°C
56
-
pH 6.0, 37°C

References & Links