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ENZYME entry: EC 3.2.1.140
| Accepted Name |
|---|
| lacto-N-biosidase.
|
| Alternative Name(s) |
|---|
| oligosaccharide lacto-N-biosylhydrolase. |
| Reaction catalysed |
|---|
| beta-D-Gal-(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-(1->4)-D-Glc + H2O <=> beta-D-galactosyl-(1->3)-N-acetyl-D-glucosamine + lactose |
| Comment(s) |
|---|
- The enzyme from Streptomyces specifically hydrolyzes the terminal
lacto-N-biosyl residue (beta-D-Gal-(1->3)-D-GlcNAc) from the non-
reducing end of oligosaccharides with the structure beta-D-Gal-
(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-(1->R).
- Lacto-N-hexaose (beta-D-Gal-(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-
(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-(1->4)-D-Glc) is hydrolyzed to
form first lacto-N-tetraose plus lacto-N-biose, with the subsequent
formation of lactose.
- Oligosaccharides in which the non-reducing terminal Gal or the
penultimate GlcNAc are replaced by fucose or sialic acid are not
substrates.
- Asialo GM1 tetraose (beta-D-Gal-(1->3)-beta-D-GalNAc-(1->3)-beta-D-
Gal-(1->4)-D-Glc) is hydrolyzed very slowly, but lacto-N-neotetraose
(beta-D-Gal-(1->4)-beta-D-GalNAc-(1->3)-beta-D-Gal-(1->4)-D-Glc) is
not a substrate.
|
| Cross-references |
|---|
| BRENDA | 3.2.1.140 |
| EC2PDB | 3.2.1.140 |
| ExplorEnz | 3.2.1.140 |
| PRIAM enzyme-specific profiles | 3.2.1.140 |
| KEGG Ligand Database for Enzyme Nomenclature | 3.2.1.140 |
| IUBMB Enzyme Nomenclature | 3.2.1.140 |
| IntEnz | 3.2.1.140 |
| MEDLINE | Find literature relating to 3.2.1.140 |
| MetaCyc | 3.2.1.140 |
| Rhea expert-curated reactions | 3.2.1.140 |
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ENZYME /
UniProtKB/Swiss-Prot entries corresponding to 3.2.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 3.2.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 3.-.-.-