The conversion of group B red blood cells into group O by an alpha-D-galactosidase from taro (Colocasia esculenta).
An alpha-D-galactosidase (EC 3.2.1.21), capable of converting group B into group O red cells, was isolated from the stem portion of taro. It was purified about 3000 fold by gel filtration and ion-exchange chromatography. The blood group-converting activity was demonstrated by hemolysis and hemagglutination studies. This activity is comparable to that of alpha-D-galactosidase isolated from coffee beans. Taro alpha-D-galactosidase also hydrolyzes (1----4)- and (1----6)-linked alpha-D-galactopyranosyl groups from D-galactose-containing glycoconjugates. Taro alpha-D-galactosidase has a low Km value (0.28mM), a low molecular weight (40,000), and a neutral optimal pH (6.0). At a final enzyme concentration of 30 units/mL in the incubation mixture, the conversion of group B into group O activity was completed within two hours, without apparent changes in the shape of the red cells.
Chien
S F
SF
Department of Chemistry, Tamkang University, Taipei, Taiwan, Republic of China.
Lin-Chu
M
M
D000017:ABO Blood-Group System; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006001:Glycoconjugates / Q000097:blood; D006384:Hemagglutination; D006461:Hemolysis; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D010945:Plants, Edible / Q000201:enzymology; D013379:Substrate Specificity; D000519:alpha-Galactosidase / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*
D000017:ABO Blood-Group System; D006001:Glycoconjugates; D000519:alpha-Galactosidase