This invention relates to novel α-galactosidases for the enzymatic removal of the immunodominant monosaccharides on blood products and tissues. Specifically this invention provides a novel family of α3 glycosidases, used for the enzymatic removal of type B antigens from blood group B and AB reactive blood products, and the GaIiIi antigen from non-human animal tissues, thereby converting these to non-immunogenic cells and tissues suitable for transplantation.