What is "lacto-n-biosidase"

Lacto-N-biosidase is an enzyme with systematic name oligosaccharide lacto-N-biosylhydrolase. 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 + HO $\rightleftharpoons$ beta-D-Gal-(1->3)-D-GlcNAc + beta-D-Gal-(1->4)-D-Glc (2) lacto-N-tetraose + HO $\rightleftharpoons$ 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).