| 英文名 |
lacto-N-biosidase |
| Example Structure |
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| 别名 |
BLLJ_1505, BLLJ_1506, lacto-N-biosidase, lacto-N-biosidase (Streptomyces strain 142), LNBase, LnbB |
| EC Number |
3.2.1.140 |
| CAS编号 |
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| Comments |
The enzyme from?Streptomyces?specifically hydrolyses the terminal lacto-N-biosyl residue (¦Â-D-Gal-(1¡ú3)-D-GlcNAc) from the non-reducing end of oligosaccharides with the structure ¦Â-D-Gal-(1¡ú3)-¦Â-D-GlcNAc-(1¡ú3)-¦Â-D-Gal-(1¡úR). Lacto-N-hexaose (¦Â-D-Gal-(1¡ú3)-¦Â-D-GlcNAc-(1¡ú3)-¦Â-D-Gal-(1¡ú3)-¦Â-D-GlcNAc-(1¡ú3)-¦Â-D-Gal-(1¡ú4)-D-Glc) is hydrolysed 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 (¦Â-D-Gal-(1¡ú3)-¦Â-D-GalNAc-(1¡ú3)-¦Â-D-Gal-(1¡ú4)-D-Glc) is hydrolysed very slowly, but lacto-N-neotetraose (¦Â-D-Gal-(1¡ú4)-¦Â-D-GalNAc-(1¡ú3)-¦Â-D-Gal-(1¡ú4)-D-Glc) is not a substrate. |
| Cofactor |
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| History |
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| Reactions |
Beta-D-Gal-(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-(1->4)-D-Glc + H(2)O = beta-D-Gal-(1->3)-D-GlcNAc + beta-D-Gal-(1->4)-D-Glc. |
