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Information on EC 2.4.1.22 - lactose synthase and Organism(s) Homo sapiens and UniProt Accession P15291

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EC Tree
     2 Transferases
         2.4 Glycosyltransferases
             2.4.1 Hexosyltransferases
                2.4.1.22 lactose synthase
IUBMB Comments
The enzyme is a complex of two proteins, A and B. In the absence of the B protein (alpha-lactalbumin), the enzyme catalyses the transfer of galactose from UDP-alpha-D-galactose to N-acetylglucosamine (EC 2.4.1.90 N-acetyllactosamine synthase).
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This record set is specific for:
Homo sapiens
UNIPROT: P15291
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Word Map
The taxonomic range for the selected organisms is: Homo sapiens
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria
Synonyms
alpha-lactalbumin, b4galt1, beta-1,4-galactosyltransferase, lacdinac, lactose synthase, lactose synthetase, beta1,4-galactosyltransferase, lalba, beta4gal-t1, ugt72b1, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
beta-1,4-galactosyltransferase
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beta-1,4-galactosyltransferase 1
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glactosyltransferase, uridine diphosphogalactose-glucose
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-
-
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lactose synthetase
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-
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N-acetyllactosamine synthase
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-
-
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UDP-galactose-glucose galactosyltransferase
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-
-
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UDPgalactose-glucose galactosyltransferase
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-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hexosyl group transfer
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-
-
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PATHWAY SOURCE
PATHWAYS
SYSTEMATIC NAME
IUBMB Comments
UDP-galactose:D-glucose 4-beta-D-galactosyltransferase
The enzyme is a complex of two proteins, A and B. In the absence of the B protein (alpha-lactalbumin), the enzyme catalyses the transfer of galactose from UDP-alpha-D-galactose to N-acetylglucosamine (EC 2.4.1.90 N-acetyllactosamine synthase).
CAS REGISTRY NUMBER
COMMENTARY hide
9030-11-9
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SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
UDP-alpha-D-galactose + D-glucose
UDP + lactose + H+
show the reaction diagram
-
-
-
?
UDP-alpha-D-galactose + O-beta-D-xylosyl-[IgG antibody]
UDP + 4-beta-D-galactosyl-O-beta-D-xylosyl-[IgG antibody]
show the reaction diagram
antibody (Lo-BM2) expressed in Nicotiana tabacum strain BY-2 cells
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-
?
UDPgalactose + D-glucose
lactose + UDP
show the reaction diagram
-
-
-
-
?
additional information
?
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the enzyme interacts with UDP-galactose transporter SLC35A2
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-
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NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
UDP-alpha-D-galactose + D-glucose
UDP + lactose + H+
show the reaction diagram
-
-
-
?
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
Formylkynurenine
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iodoacetate
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N-Acetylimidazole
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ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
alpha-lactalbumin
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alters the acceptor specificity of the galactosyltransferase and thereby increases lactose synthesis and decreases N-acetylglucosamine synthesis
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
3.4
glucose
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-
additional information
additional information
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
SwissProt
Manually annotated by BRENDA team
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
-
-
-
Manually annotated by BRENDA team
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
B4GT1_HUMAN
398
1
43920
Swiss-Prot
Mitochondrion (Reliability: 4)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
75000
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gel filtration
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
homodimer
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additional information
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
carbohydrate characterization of an antibody (Lo-BM2) expressed in Nicotiana tabacum strain BY-2 cells shows that the purified Lo-BM2 displays N-glycan homogeneity with a high proportion (about 70%) of the complex GnGnXF glycoform. The stable co-expression of a human beta-1,4-galactosyltransferase targeted to different Golgi subcompartments alters Lo-BM2N-glycosylation and results in the production of an antibody that exhibits either hybrid structures containing a low abundance of the plant epitopes (alpha-1,3-fucose and beta-1,2-xylose), or a large amount of galactose-extended N-glycan structures. Targeting of GalT to different Golgi subcompartments. The sequence corresponding to the catalytic region (amino acid residues 123-397) of the human GalT precursor is fused via a SpeI restriction site to the first 77 amino acids from Nicotiana tabacum GNTI, corresponding to the CTS domain
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
galactosyl transferase component
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expressed in CHO and Lec8 cells
gene B4GALT1, recombinant co-expression of a human IgG2 with a chimeric human GalT targeted to the cis- or trans-Golgi in Nicotiana tabacum strain BY-2 cell microsomes
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Hill, R.L.; Brew, K.
Lactose synthetase
Adv. Enzymol. Relat. Areas Mol. Biol.
43
411-490
1975
Bos taurus, Capra hircus, Cavia porcellus, Ovis aries, Homo sapiens, Mammalia, Sus scrofa
Manually annotated by BRENDA team
Ebner, K.E.
Lactose synthetase
The Enzymes, 3rd Ed. (Boyer, P. D. , ed. )
9
363-377
1973
Bos taurus, Capra hircus, Ovis aries, Homo sapiens, Mammalia, Mus musculus, Sus scrofa
-
Manually annotated by BRENDA team
Fujita-Yamaguchi, Y.; Yoshida, A.
Purification and characterization of human serum galactosyltransferase (lactose synthetase A protein)
J. Biol. Chem.
256
2701-2706
1981
Homo sapiens
Manually annotated by BRENDA team
Wiertelak, W.; Sosicka, P.; Olczak, M.; Maszczak-Seneczko, D.
Analysis of homologous and heterologous interactions between UDP-galactose transporter and beta-1,4-galactosyltransferase 1 using NanoBiT
Anal. Biochem.
593
113599
2020
Homo sapiens (P15291)
Manually annotated by BRENDA team
Navarre, C.; Smargiasso, N.; Duvivier, L.; Nader, J.; Far, J.; De Pauw, E.; Boutry, M.
N-Glycosylation of an IgG antibody secreted by Nicotiana tabacum BY-2 cells can be modulated through co-expression of human beta-1,4-galactosyltransferase
Transgenic Res.
26
375-384
2017
Homo sapiens (P15291)
Manually annotated by BRENDA team