This invention relates to enzymatic removal of type A and B antigens from blood group A, B, and AB reactive cells in blood products, and thereby converting these to non-A and non-B reactive cells. The invention further relates to using unique α-N-acetylgalactosaminidases and α-galactosidases with superior kinetic properties for removing the immunodominant monosaccharides of the blood group A and B antigens and improved performance in enzymatic conversion of red blood cells. The preferred unique α-N-acetylgalactosaminidases and α-galactosidases exhibit the following characteristics: (i) exclusive, preferred or no less than 10% substrate specificity for the type A and B branched polysaccharide structures relative to measurable activity with simple mono- and disaccharide structures and aglycon derivatives hereof; (ii) optimal performance at neutral pH with blood group oligosaccharides and in enzymatic conversion of cells; and (iii) a favorable kinetic constant K m with mono- and oligosaccharide substrates. The conversion methods of the invention use significantly lower amounts of recombinant glycosidase enzymes than previous and result in complete sero-conversion of all blood group A and B red cells.
1. An isolated Streptomyces griseoplanus cell of a Streptomyces griseoplanus cell line deposited with ATCC under Deposit No. PTA-4077.
2. The isolated Streptomyces griseoplanus cell of claim 1 that expresses an α-galactosidase for removing immunodominant α-galactose monosaccharides from blood group B or AB reactive cells of blood products, wherein the α-galactosidase is active at said removing at neutral pH.
3. The isolated Streptomyces griseoplanus cell of claim 2 , wherein said α-galactosidase has no detectable activity with an α-Gal p-nitrophenyl monosaccharide derivative.
4. The isolated Streptomyces griseoplanus cell of claim 2 , wherein said α-galactosidase has no detectable activity with a P 1 antigen.