FIELD: biochemistry, enzymes. SUBSTANCE: strain of bacterium Pseudoalteromonas sp. VKM B-2135 D is used as a producer of galactosidase that is capable to remove α-1,3-bound galactose residues from glycoproteins of B-blood substances and to convert the latter to substances of group H (0). Strain is isolated from sea water by method of direct plating. Strain is cultured on medium of the following composition, g/l: bactopeptone 5.0; glucose 1.0; K2HPO4 0.2; yeast extract (Difco) 2.0; distilled water 500 ml, and sea water 500 ml at pH 7.8, at 25 C for 24 h. Culture produces α-galactosidase. Preparation of α-galactosidase is isolated from biomass by its releasing from cells by ultrasonic treatment followed by enzyme purification by ion-exchange chromatography on DEAE-Toyoperl 650-M, gel-filtration on Sepharose CL-4B and rechromatography on DEAE-Toyoperl 650-M. The yield of α-galactosidase preparation at specific activity 10 U/mg protein is 30% of its content in crude extract. Enzyme shows optimum pH at 6.7-7.7, molecular mass 200 kDa. Enzyme inactivates the group specificity of human blood-B erythrocytes. Invention can be used in microbiology, biotechnology and medicine. EFFECT: strain of bacterium indicated above, improved method of enzyme preparing, increased yield of enzyme. 3 tbl
