Methods are provided for making bispecific antibodies and antibody conjugates comprising site-specifically cross-linking two or more antibodies, antibody fragments or Fc-fusion proteins. Also provided are compositions and uses for the bispecific antibodies and antibody conjugates. The bispecific antibodies may be used to treat a disease or condition. Also provided are methods for site-specifically conjugating a liposome, an mRNA or an siRNA to an antibody, and uses of the antibody-conjugated liposome, mRNA or siRNA.

A mutant of Endos2 includes one or more mutations in the sequence of a wild-type EndoS2 (SEQ ID NO:1), wherein the one or more mutations are in a peptide region located within residues 133-143, residues 177-182, residues 184-189, residues 221-231, and/or residues 227-237, wherein the mutant of EndoS2 has a low hydrolyzing activity and a high tranglycosylation activity, as compared to those of the wild-type EndoS2. A method for preparing an engineered glycoprotein using the mutant of EndoS2 includes coupling an activated oligosaccharide to a glycoprotein acceptor. The activated oligosaccharide is a glycan oxazoline.

A method for making a milk product (e.g. a yogurt) comprising adding an effective amount of an N-linked glycosidase and/or an O-linked glycosidase to milk.

The present invention provides endo-?-N-acetylglucosaminidase (Endo-Si) cloning from a strain belonging to Streptococcus iniae and a mutant enzyme thereof, a gene encoding the enzyme, a recombinant plasmid, a transformant obtained by transformation of a cell by the plasmid and use thereof, and a method for producing e.g., a sugar chain remodeled antibody using the enzyme. A polypeptide having an amino acid sequence at amino acid positions 34 to 928 in SEQ ID NO: 2 or an amino acid sequence having the same amino acid sequence except containing one or mutations at more amino acid positions selected from the group consisting of amino acids at position 241 (D241), 190 (T190), 311 (Q311) and 360 (E360), said polypeptide exhibiting a sugar chain hydrolysis activity and/or transglycosylation activity.

The present disclosure provides a one-pot chemoenzymatic method for site-specific modification and conjugation of antibodies at their Fc glycan site to produce structurally well-defined antibody conjugates carrying defined drugs and other entities. The method is enabled by the discovery that certain endoglycosidases have the ability to both deglycosylate an antibody and to recognize selectively modified small disaccharide oxazolines for transglycosylation on antibodies without hydrolysis of the resulting products.

Provided herein is an -fucosidase that can cleave a conjugate comprising an N-glycan and a label where the label is added by amine reactive chemistry. The -fucosidase also has an accelerated reaction time using Schiff base labeled N-glycans compared with BKF. A reaction mix, enzyme mix and kit comprising the -fucosidase are provided, as well as a method for analyzing glycoproteins. The -fucosidase finds particular use in analyzing the N-glycans of therapeutic glycoproteins.

Provided herein are deglycosylating enzymes that remove a broad range of N-glycans from N-glycosylated proteins. Further provided are methods of recombinantly producing and expressing the deglycosylating enzymes. The presently described deglycosylating enzymes can be used to produce free glycans for characterization, and for prebiotic and immunostimulatory uses. In addition, the presently described deglycosylating enzymes can be used to produce deglycosylated proteins for characterization, to improve digestion, and to reduce immunogenicity.

The present invention provides an EndoS mutant enzyme having an amino acid sequence of EndoS D233Q and further having a particular additional mutation and exhibiting a reduced hydrolysis activity, in comparison with the activity of EndoS D233Q, to an N-linked sugar chain (N297-linked sugar chain) linked to Asn at position 297 in IgG and a gene encoding the same.

The present application relates to the field of glyco-engineering and, more specifically, to eukaryotic cells wherein both an endoglucosaminidase is present and made deficient in UDP-galactose 4-epimerase (GalE). Typically, a glycoprotein is also present in the cells. These cells can be used to deglycosylate or partly deglycosylate the (exogenous) glycoprotein, in particular, without the need for adding an extra enzyme. Methods are also provided for the application of these cells in protein production.

The present invention provides for recombinant Endo-S mutants that exhibit reduced hydrolysis activity and increased transglycosylation activity for the synthesis of glycoproteins wherein a desired sialylated oxazoline or synthetic oligosaccharide oxazoline is added to a core fucosylated or nonfucosylated GlcNAc-protein acceptor. Such recombinant Endo-S mutants are useful for efficient glycosylation remodeling of IgG1-Fc domain to provide different antibody glycoforms carrying structurally well-defined Fc N-glycans.