The conversion of group B red blood cells into group O by an α-d-galactosidase from taro (Colocasia esculenta)
✍ Scribed by Su-Fang Chien; Marie Lin-Chu
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 706 KB
- Volume
- 217
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
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.