The appearance of peptides is measured as tyrosine equivalent at 275 nm by spectrophotometry.
One unit causes the increase of optical density at 275 nm corresponding to one micromole of tyrosine per minute under the conditions described below.
At the same time, prepare the blank by first mixing the substrate solution with 3.2mL of TCA mixture (B) after 10 min-incubation at 30 ℃, followed by addition of the enzyme solution, and carry out the same procedure (procedure 4－5) at test (OD blank).
* Dissolve the enzyme preparation in ice-cold 10 mM borax-NaOH buffer, pH 11.0 and dilute to 0.1－0.4U/mL with enzyme diluent (C), immediately before assay.
Activity can be calculated by using the following formula：
Weight activity (U/mg)＝(U/mL)×1/C
This procedure is for informational purposes.