en بیوشیمی Biochemistry مقالات اصلی Original Article <div style="text-align: justify;"><strong><em>Background</em></strong>: Because it tends to cause deterioration in the quality of food and appearance, food browning&nbsp;is unacceptable. Tyrosinase, which catalyzes the transformation of mono phenolic compounds into oquinones,&nbsp;has been associated with this phenomenon. Natural anti-browning agents were used to help&nbsp;avoid the enzymatic browning that occurs in many foods.<br> <br> <strong><em>Methods:</em></strong> Tyrosinase of Jerusalem Artichoke tubers was purified through (NH4)2SO4 sedimentation,&nbsp;dialysis, chromatography, and finally gel&nbsp; electrophoresis. The purified enzyme was characterized and&nbsp;inhibited by rosemary extracts.<br> <br> <strong><em>Results:</em></strong> Purification of tyrosinase from Jerusalem Artichoke tuber were accomplished. The specific&nbsp;activity at the final step of purification increased to 14115.76 U/mg protein with purification fold 32.89&nbsp;using CM-Cellulose chromatography. The molecular mass was evaluated by electrophoresis and found<br> to be 62 KDa. Maximum tyrosinase activity was found at 30 &deg;C, pH 7.2, and higher affinity towards Ltyrosine.&nbsp;Inhibition percentage of heated extracts for leaves and flowers on tyrosinase activity was better&nbsp;than nonheated with 29.65% and 23.75%, respectively. The kinetic analysis exposed uncompetitive<br> inhibition by leaves and flowers heated extracts.<br> <br> <strong><em>Conclusions:</em></strong> In this study, we concluded the usage of natural anti-browning inhibitors like rosemary&nbsp;extract be able to be castoff to substitute the chemical agents which might be dangerous to social&nbsp;healthiness. Natural anti-browning agents can be used to prevent the browning of many foods.</div> Keywords: Tyrosinase, Jerusalem artichoke, Rosemary 495 505 http://rbmb.net/browse.php?a_code=A-10-714-1&slc_lang=en&sid=1 Omar Younis Al-abbasy chem.omar1978@uomosul.edu.iq. 100319475328460012577 100319475328460012577 Yes Chem. Dept. College of Education for pure science. University of Mosul, Mosul Iraq. Wathba Idrees Ali 100319475328460012578 100319475328460012578 No Chem. Dept. College of Education for pure science. University of Mosul, Mosul Iraq. 2: Medical Aya Ihsan Rashan 100319475328460012579 100319475328460012579 No Medical Laboratory Techniques Dept. Al-Hadba University College, Mosul, Iraq. Shihab Ahmed Al-bajari 100319475328460012580 100319475328460012580 No Pathologic Analysis, Mosul Technical, Northern Technical University, Mosul, Iraq.