Omar Younis Al-abbasy - Chem. Dept. College of Education for pure science. University of Mosul, Mosul Iraq.
Wathba Idrees Ali - Chem. Dept. College of Education for pure science. University of Mosul, Mosul Iraq. ۲: Medical
Aya Ihsan Rashan - Medical Laboratory Techniques Dept. Al-Hadba University College, Mosul, Iraq.
Shihab Ahmed Al-bajari - Pathologic Analysis, Mosul Technical, Northern Technical University, Mosul, Iraq.

Background: Because it tends to cause deterioration in the quality of food and appearance, food browning is unacceptable. Tyrosinase, which catalyzes the transformation of mono phenolic compounds into oquinones, has been associated with this phenomenon. Natural anti-browning agents were used to help avoid the enzymatic browning that occurs in many foods. Methods: Tyrosinase of Jerusalem Artichoke tubers was purified through (NH۴)۲SO۴ sedimentation, dialysis, chromatography, and finally gel  electrophoresis. The purified enzyme was characterized and inhibited by rosemary extracts. Results: Purification of tyrosinase from Jerusalem Artichoke tuber were accomplished. The specific activity at the final step of purification increased to ۱۴۱۱۵.۷۶ U/mg protein with purification fold ۳۲.۸۹ using CM-Cellulose chromatography. The molecular mass was evaluated by electrophoresis and found to be ۶۲ KDa. Maximum tyrosinase activity was found at ۳۰ °C, pH ۷.۲, and higher affinity towards Ltyrosine. Inhibition percentage of heated extracts for leaves and flowers on tyrosinase activity was better than nonheated with ۲۹.۶۵% and ۲۳.۷۵%, respectively. The kinetic analysis exposed uncompetitive inhibition by leaves and flowers heated extracts. Conclusions: In this study, we concluded the usage of natural anti-browning inhibitors like rosemary extract be able to be castoff to substitute the chemical agents which might be dangerous to social healthiness. Natural anti-browning agents can be used to prevent the browning of many foods.

Keywords: Tyrosinase, Jerusalem artichoke, Rosemary