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ENZYME entry: EC

Accepted Name
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
  • 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.
PRIAM enzyme-specific profiles3.2.1.140
KEGG Ligand Database for Enzyme Nomenclature3.2.1.140
IUBMB Enzyme Nomenclature3.2.1.140
MEDLINEFind literature relating to
Rhea expert-curated reactions3.2.1.140

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