Levansucrase expressed a specific fructosidase activity of 2.9 units per milligram (U mg -1 ), where 1 unit is defined as the amount of enzyme releasing 1 μmol of glucose per minute at a working temperature of 37°C and a sucrose concentration of 100 g L −1 at pH 6.0 (50 mM potassium phosphate buffer).
Source: wiktionary