Abstract: The present invention relates to the conjugation of a tubulysin analog compound to a cell-binding molecule with branched/side-chain linkers for having better delivery of the conjugate compound and targeted treatment of abnormal cells. It also relates to a branched-linkage method of conjugation of a tubulysin analog molecule to a cell-binding ligand, as well as methods of using the conjugate in targeted treatment of cancer, infection and autoimmune disease.

Abstract: Methods for producing oligosaccharide products such as difucosylated oligosaccharides are disclosed. The methods include culturing recombinant cells in a cell culture medium comprising L-fucose, an oligosaccharide acceptor, and a carbon source. The cells are cultured under conditions in which a first fucosyltransferase polypeptide having a first substrate selectivity (e.g., an ?1-2-fucosyltransferase polypeptide), a second fucosyltransferase polypeptide having a second substrate specificity (e.g., an ?1-3-fucosyltransferase polypeptide), a nucleotide sugar pyrophosphorylase polypeptide, a lactose transporter polypeptide, and an L-fucose transporter polypeptide are expressed, and in which the oligosaccharide acceptor is converted to the difucosylated oligosaccharide. Recombinant cells for use in the methods are also described.