Ultraviolet irradiation effect on characteristics of protease enzyme from African catfish (Clarias sp.) intestines

Abstract

Abstract The goal of this study was to investigate the impact of UV-C irradiation on the activity of crude enzymes derived from African Catfish intestines as well the optimum conditions for subsequent autolysis processes. Three key variables were assessed: UV-C exposure time, pH and temperature. The experiments involved the homogenization of intestines in cold distilled water followed by subjecting the mixture into UV-C treatment for exposure times of 0, 10, 20 and 30 minutes. After centrifugation process, the collected supernatant was utilized as the crude enzyme. At various level of temperature (40, 50, 60°C) and pH (6, 7, 8) the activity of crude enzyme was assayed with casein as substrate. The findings revealed the increasing of EA as the UV-C exposure time decreased and pH increased, while the highest EA value was observed at temperature of 50°C. Consequently, the optimal conditions were identified as follows: 0 minutes of UV-C exposure time, pH of 8, and temperature of 50°C. Furthermore, UV-Vis absorption, FTIR, and fluorescence spectroscopy of the crude enzyme after UV-C irradiation induction was studied to investigate the its conformational changes. These additional analyses provided valuable insights into the structural alterations of the crude enzyme caused by the UV-C treatment.