Abstract

Isolation and characterization of protease from the skin of mature papaya (Carica papaya L.)

Author(s): Niranjan Kumar Sana, Md.Rezaul Karim, Bidhan Chandra Sarkar, Goutam Kumar Sarker, Md.Entazul Huque, Ranajit Kumar Shaha

A proteolytic enzyme was purified from the skin of papaya (Carica papaya L.) using gel filtration on Sephadex G-100 followed by ion exchange chromatography on DEAE-cellulose to the homogeneous state as confirmed by slab gel electrophoresis. The molecular weight of the purified enzyme was estimated to be 25 kDa and 24 kDa by gel filtration chromatography and SDS-PAGE, respectively. The purified enzyme showedmaximumactivity at pH 8.0 and at temperature 440C. The enzyme was able to hydrolyze casein, azoalbumin, azocasein, hemoglobin and gelatin with high specific activity but keratin and collagen was found to be not degraded. Metallic ions Mg2+, Mn2+, Cd2+ and Li+ have no effect on proteolytic activities but EDTA, urea, Ca2+ and Zn2+ have an activator effect. Fe2+, Fe3+, Hg2+, Cu2+ and Ag+ have strong inhibitory effect on proteolytic activities. The Km value of the enzyme was found to be 45 M for casein as substrate.