Blood group B degrading activity of Ruminococcus gnavus alpha-galactosidase

Ruminococcus gnavus is a Gram positive, nonspore-forming obligate anaerobe normally found in the human alimentary tract. In culture, this organism constitutively produces a 1-3 alpha-galactosidase. We fractionated and characterized this enzyme demonstrating hydrolysis of the B epitope on erythrocyte membranes and seroconversion to H epitope (blood type O). Since the enzyme yield was low, cell suspension studies could not be performed. Instead, hydrolysis of the B membrane epitope was studied with an ELISA. A highly purified enzyme product was analyzed for characteristics such as pH, ionic strength, and temperature optimum. Activity in red cell preservative solutions and in the presence of type B plasma was also demonstrated. Ruminococcus gnavus a 1-3 alpha-galactosidase has potential application in the enzymatic conversion of type B to O packed red blood cell units.