CATH Classification

Domain Context

CATH Clusters

Superfamily Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A
Functional Family beta-1,4-galactosyltransferase 1

Enzyme Information

2.4.1.90
N-acetyllactosamine synthase.
based on mapping to UniProt P08037
UDP-alpha-D-galactose + N-acetyl-D-glucosamine = UDP + N-acetyllactosamine.
-!- The reaction is catalyzed by a component of EC 2.4.1.22, which is identical with EC 2.4.1.38, and by an enzyme from the Golgi apparatus of animal tissues. -!- Formerly EC 2.4.1.98.
2.4.1.38
Beta-N-acetylglucosaminylglycopeptide beta-1,4-galactosyltransferase.
based on mapping to UniProt P08037
UDP-alpha-D-galactose + N-acetyl-beta-D-glucosaminylglycopeptide = UDP + beta-D-galactosyl-(1->4)-N-acetyl-beta-D-glucosaminylglycopeptide.
-!- Terminal N-acetyl-beta-D-glucosaminyl residues in polysaccharides, glycoproteins and glycopeptides can act as acceptor. -!- High activity is shown toward such residues in branched-chain polysaccharides when these are linked by beta-1,6 links to galactose residues; lower activity toward residues linked to galactose by beta- 1,3 links. -!- A component of EC 2.4.1.22.
2.4.1.22
Lactose synthase.
based on mapping to UniProt P08037
UDP-alpha-D-galactose + D-glucose = UDP + lactose.
-!- 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).
2.4.1.-
Hexosyltransferases.
based on mapping to UniProt P08037

UniProtKB Entries (2)

P29752
LALBA_MOUSE
Mus musculus
Alpha-lactalbumin
P08037
B4GT1_BOVIN
Bos taurus
Beta-1,4-galactosyltransferase 1

PDB Structure

PDB 1NMM
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
alpha-Lactalbumin (LA) stimulates milk beta-1,4-galactosyltransferase I (beta 4Gal-T1) to transfer glucose from UDP-glucose to N-acetylglucosamine. Crystal structure of beta 4Gal-T1 x LA complex with UDP-Glc.
Ramakrishnan, B., Shah, P.S., Qasba, P.K.
J.Biol.Chem.