Biotinylated β-galactosidase is prepared from an enzyme of exceptionally high specific activity isolated from a special strain of E. coli. Unlike mammalian β-galactosidase, the activity of this E. coli enzyme is optimal at an alkaline pH, enabling it to be used free of interference from endogenous enzyme activity. For many applications, Avidin D followed by biotinylated β-galactosidase affords a highly sensitive system which can be used in a variety of enzyme immunoassays, including screening for monoclonal antibodies.One unit is 1 µmole o-nitrophenyl-β-D-galacto-pyranoside hydrolyzed per min. at 37 °C, pH 7.3. |
