Lacto-N-biosidase explained

Lacto-N-biosidase
Ec Number:	3.2.1.140
Cas Number:	146359-52-6

Lacto-N-biosidase is an enzyme with systematic name oligosaccharide lacto-N-biosylhydrolase.^{[1] [2]} This enzyme catalyses the following chemical reaction

(1) beta-D-Gal-(1->3)-beta-D-GlcNAc-(1->3)-beta-D-Gal-(1->4)-D-Glc + H₂O

\rightleftharpoons beta-D-Gal-(1->3)-D-GlcNAc + beta-D-Gal-(1->4)-D-Glc

(2) lacto-N-tetraose + H₂O

\rightleftharpoons lacto-N-biose + lactose

The enzyme from Streptomyces specifically hydrolyses 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).

Notes and References

1. Sano M, Hayakawa K, Kato I . An enzyme releasing lacto-N-biose from oligosaccharides . Proceedings of the National Academy of Sciences of the United States of America . 89 . 18 . 8512–8516 . September 1992 . 1528855 . 49950 . 10.1073/pnas.89.18.8512 . free .
2. Sano M, Hayakawa K, Kato I . Purification and characterization of an enzyme releasing lacto-N-biose from oligosaccharides with type 1 chain . The Journal of Biological Chemistry . 268 . 25 . 18560–18566 . September 1993 . 10.1016/S0021-9258(17)46664-6 . 7689556 . free .