The appearance of quinoneimine dye is measured at 550 nm by spectrophotometry.
One unit causes the formation of one micromole of hydrogen peroxide (half of a micromole of quinoneimine dye) per minute under the conditions described below.
At the same time, measure the blank rate (ΔOD blank) by using the same method as the test except that the enzyme diluent is added instead of the enzyme solution.
* Dissolve the enzyme preparation in ice-cold enzyme diluent (J), dilute to 0.1－0.5 U/mL with the same buffer and store on ice.
Activity can be calculated by using the following formula：
Weight activity (U/mg)＝(U/mL)×1/C