_EC 2.4.1.22 Lactose synthase. 37 PDB entries  
EC 2.-.-.- Transferases. [17,949 PDB entries]
EC 2.4.-.- Glycosyltransferases. [1,920 PDB entries]
EC 2.4.1.- Hexosyltransferases. [944 PDB entries]
EC 2.4.1.22 Lactose synthase. [37 PDB entries]    
1fgx

Reaction: UDP-alpha-D-galactose + D-glucose = Udp + lactose.
 

UDP-alpha-D-galactose
+
D-glucose
=
UDP
+
lactose
Molecule diagrams generated from .mol files obtained from the KEGG ftp site.

Other name(s): N-acetyllactosamine synthase. UDP-galactose--glucose galactosyltransferase.
Comments: The enzyme is a complex of 2 proteins A and b. In the absence of the B protein (alpha-lactalbumin) the enzyme catalyzes the transfer of galactose from UDP-galactose to N-acetylglucosamine (cf. Ec 2.4.1.90).
Links:   [IntEnz]   [ExPASy]   [KEGG]  

There are 37 PDB entries in enzyme class E.C.2.4.1.22

  PDB code Protein
1fgx
Crystal structure of the bovine beta 1,4 galactosyltransferase (b4galt1) catalytic domain complexed with ump
Source: Bos taurus. Cattle. Organism_taxid: 9913. Organ: liver. Expressed in: mus musculus. Expression_system_taxid: 10090. Expression_system_cell_line: nso.
Chains: A, B (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group U5P is 84.00% similar to enzyme product UDP
1fr8
Crystal structure of the bovine beta 1,4 galactosyltransferase (b4galt1) catalytic domain complexed with uridine diphosphogalactose
Source: Bos taurus. Cattle. Organism_taxid: 9913. Organ: liver. Expressed in: mus musculus. Expression_system_taxid: 10090. Expression_system_cell_line: nso.
Chains: A, B (271 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group GDU corresponds to enzyme product UDP
1nf5
Crystal structure of lactose synthase, complex with glucose
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: lalba. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group BGC corresponds to enzyme reactant D-glucose
1nhe
Crystal structure of lactose synthase complex with udp
Source: Mus musculus. House mouse. Organism_taxid: 10090. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group UDP corresponds to enzyme product UDP
1nkh
Crystal structure of lactose synthase complex with udp and manganese
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: alpha-lactalbumin. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group UDP corresponds to enzyme product UDP
1nmm
Beta-1,4-galactosyltransferase mutant cys342thr complex with lactalbumin and glcnac
Source: Mus musculus. House mouse. Organism_taxid: 10090. Variant: bl21. Expressed in: escherichia coli. Expression_system_taxid: 562. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group NAG is 68.75% similar to enzyme reactant D-glucose
1nqi
Crystal structure of lactose synthase, a 1:1 complex between galactosyltransferase and alpha-lactalbumin in the presence
Source: Mus musculus. House mouse. Organism_taxid: 10090. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group NAG is 68.75% similar to enzyme reactant D-glucose
1nwg
Beta-1,4-galactosyltransferase complex with alpha- lactalbumin and n-butanoyl-glucoamine
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: lalba. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group BGN is 61.00% similar to enzyme reactant D-glucose
1o0r
Crystal structure of the catalytic domain of bovine beta1,4- galactosyltransferase complex with udp-galactose
Source: Bos taurus. Cattle. Organism_taxid: 9913. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.
Chains: A, B (271 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group GDU corresponds to enzyme reactant UDP-galactose
  Het Group DIO is 50.00% similar to enzyme reactant D-glucose
1o23
Crystal structure of lactose synthase in the presence of udp
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: lalba. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group UPG is 69.44% similar to enzyme product UDP
1oqm
A 1:1 complex between alpha-lactalbumin and beta1,4- galactosyltransferase in the presence of udp-n-acetyl- galactosamine
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: lalba. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UD2 is 87.00% similar to enzyme reactant UDP-galactose
  Het Group PG4 is 58.00% similar to enzyme reactant D-glucose
1pzt
Crystal structure of w314a-beta-1,4-galactosyltransferase (b4gal-t1) catalytic domain without substrate
Source: Bos taurus. Cattle. Organism_taxid: 9913. Gene: b4galt1, ggtb2 or galt. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.
Chain: A (271 residues) CATH domain: 3.90.550.10
1pzy
W314a-beta1,4-galactosyltransferase-i complexed with alpha-l in the presence of n-acetylglucosamine, udp and manganese
Source: Mus musculus. House mouse. Organism_taxid: 10090. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913. Other_details: n-terminal carries a tag containing 13 amino
Chains: B, D (271 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group NAG is 68.75% similar to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
1tvy
Beta-1,4-galactosyltransferase mutant met344his (m344h-gal- t1) complex with udp-galactose and manganese
Source: Bos taurus. Cattle. Organism_taxid: 9913. Gene: b4galt1. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal 13 amino acids belong to t7-tag from the vector
Chains: A, B (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group GDU corresponds to enzyme reactant UDP-galactose
1tw1
Beta-1,4-galactosyltransferase mutant met344his (m344h-gal- t1) complex with udp-galactose and magnesium
Source: Bos taurus. Cattle. Organism_taxid: 9913. Gene: b4galt1. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal 13 amino acids belong to t7-tag from the vector
Chains: A, B (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group GDU corresponds to enzyme reactant UDP-galactose
  Het Group DIO is 50.00% similar to enzyme reactant D-glucose
1tw5
Beta1,4-galactosyltransferase mutant m344h-gal-t1 in complex with chitobiose
Source: Bos taurus. Cattle. Organism_taxid: 9913. Gene: b4galt1. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal 13 amino acids belong to t7-tag from the vector
Chains: A, B (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.00% similar to enzyme reactant UDP-galactose
  Het Group DIO is 50.00% similar to enzyme reactant D-glucose
  Het Group CBS is 67.00% similar to enzyme product lactose
1yro
Crystal structure of beta14,-galactosyltransferase mutant arg228lys in complex with alpha-lactalbumin in the presence of udp-galactose and mn
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: alpha-lactalbumin. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group GDU corresponds to enzyme reactant UDP-galactose
2ae7
Crystal structure of human m340h-beta1,4-galactosyltransfera (m340h-b4gal-t1) in complex with pentasaccharide
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693. Other_details: n-terminal carries t7 tag of 11 amino acids by gly, ser & ala
Chains: A, B, C (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.78% similar to enzyme reactant UDP-galactose
  Het Group MAN corresponds to enzyme reactant D-glucose
2aec
Crystal structure of human m340h-beta1,4-galactosyltransfera (m340h-b4gal-t1) in complex with glcnac-beta1,2-man-alpha1, beta-or
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal carries t7 tag of 11 amino acids by gly, ser & ala
Chains: A, B, C (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.78% similar to enzyme reactant UDP-galactose
  Het Group BMA corresponds to enzyme reactant D-glucose
2aes
Crystal structure of human m340h-beta1,4-galactosyltransfera (m340h-b4gal-t1) in complex with glcnac-beta1,2-man-alpha1, beta-or
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal carries t7 tag of 11 amino acids by gly, ser & ala
Chains: A, B, C (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.78% similar to enzyme reactant UDP-galactose
  Het Group BMA corresponds to enzyme reactant D-glucose
2agd
Crystal structure of human m340h-beta-1,4-galactosyltransfer i(m340h-b4gal-t1) in complex with glcnac-beta1,4-man-alpha1 beta-or
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal carries t7 tag of 11 amino acids by gly, ser & ala
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.78% similar to enzyme reactant UDP-galactose
  Het Group BMA corresponds to enzyme reactant D-glucose
2ah9
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with chitotriose
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: n-terminal carries t7 tag of 11 amino acids by gly, ser & ala
Chains: A, B, C (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.78% similar to enzyme reactant UDP-galactose
  Het Group DIO is 50.00% similar to enzyme reactant D-glucose
  Het Group CTO is 46.67% similar to enzyme product lactose
2fy7
Crystal structure of the catalytic domain of the human beta1,4-galactosyltransferase mutant m339h in apo form
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.
Chain: A (268 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group PGE is 46.00% similar to enzyme reactant D-glucose
2fya
Crystal structure of the catalytic domain of the human beta1, 4-galactosyltransferase mutant m339h complex with manganese
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.
Chain: A (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group PGE is 46.00% similar to enzyme reactant D-glucose
2fyb
Crystal structure of the catalytic domain of the human beta1,4-galactosyltransferase mutant m339h in complex with mn and udp-galactose in open conformation
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.
Chain: A (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group UDP corresponds to enzyme product UDP
2fyc
Crystal structure of the catalytic domain of bovine beta1,4- galactosyltransferase-i in complex with alpha-lactalbumin, ca and udp-galactose
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: lalba. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligand:   Het Group GDU corresponds to enzyme reactant UDP-galactose
2fyd
Catalytic domain of bovine beta 1, 4-galactosyltransferase in complex with alpha-lactalbumin, glucose, mn, and udp-n- acetylgalactosamine
Source: Mus musculus. House mouse. Organism_taxid: 10090. Gene: lalba. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.
Chains: B, D (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group BGC corresponds to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
3ee5
Crystal structure of human m340h-beta1,4-galactosyltransfera (m340h-b4gal-t1) in complex with glcnac-beta1,3-gal-beta- naphthalenemethanol
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 562.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDH is 83.78% similar to enzyme reactant UDP-galactose
  Het Group GAL is 91.67% similar to enzyme reactant D-glucose
4ee3
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with pentasaccharide
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, beta4gal-t1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group BGC corresponds to enzyme reactant D-glucose
  Het Group UDH is 78.12% similar to enzyme product UDP
4ee4
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with tetrasaccharide from lacto neohexose
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group BGC corresponds to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
4ee5
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with trisaccharide from lacto-n neotetraose
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group BGC corresponds to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
4eea
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with glcnac-beta1,6-gal-beta1,4
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group BGC corresponds to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
4eeg
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with glcnac-beta1,6-gal-beta
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group GAL corresponds to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
4eem
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with glcnac-beta1,6-man-alpha-m
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group MMA is 92.31% similar to enzyme reactant D-glucose
  Het Group UDP corresponds to enzyme product UDP
4eeo
Crystal structure of human m340h-beta-1,4-galactosyltransfer (m340h-b4gal-t1) in complex with glcnac-beta1,6-glcnac-alph
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: b4galt1, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B, C (273 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group UDP corresponds to enzyme product UDP
  Het Group BBV is 50.00% similar to enzyme product lactose
4krv
Crystal structure of catalytic domain of bovine beta1,4- galactosyltransferase mutant m344h-galt1 complex with 6-sul
Source: Bos taurus. Bovine,cow,domestic cattle,domestic cow. Organism_taxid: 9913. Gene: b4galt1, galt, ggtb2. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Chains: A, B (272 residues) CATH domain: 3.90.550.10
Bound ligands:   Het Group NGS is 55.00% similar to enzyme reactant D-glucose
  Het Group UDH is 78.12% similar to enzyme product UDP
4l41
Human lactose synthase: a 2:1 complex between human alpha-la and human beta1,4-galactosyltransferase
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: 4-galactosyltransferase, beta1, lalba, lyzl7. Expressed in: escherichia coli. Expression_system_taxid: 511693. Gene: alpha-lactalbumin, b4galt1, ggtb2.
Chain: C (273 residues) CATH domain: 3.90.550.10