FIGURE 1.

Analysis of the citrulline aminopeptidase activity by double layer fluorescent zymography. The citrulline aminopeptidase activity in rat epidermis extracts was analyzed by double layer fluorescent zymography. Samples were loaded onto a 5% polyacrylamide gel at 4 °C. Following native PAGE, the gel was washed and immersed in 0.1 m phosphate buffer (pH 6.0) (A) and 0.1 m Tris-HCl (pH 7.5) (B and C) for 30 min and then covered with a 0.1 mm Cit-MCA fluorescent substrate membrane to create a double layer prior to incubation at 37 °C for 30 min. White bands of fluorescent activity generated from the citrulline aminopeptidase located in the double layer were clearly observed on the UV transilluminator. Lane 1, newborn rat epidermis extracts; lane 2, 6-week-old rat kidney extracts; lane 3, rat BH.