Isolasi dan Karakterisasi Enzim Xantin Oksidase dari Susu Kambing
Isolation and Characterization of Xanthine Oxidase Enzyme from Goat Milk
Enzim xantin oksidase (XO) berperan dalam pembentukan asam urat dan dapat diperoleh dari berbagai sumber, salah satunya susu kambing. Penelitian ini bertujuan untuk menyediakan enzim xantin oksidase yang telah diketahui kemurnian, karakteristik (pH, suhu, dan berat molekul), serta mengetahui pengaruh inhibitor allopurinol terhadap aktivitas enzim XO. Isolasi dilakukan menggunakan NaCl, dilanjutkan dengan pemurnian parsial melalui presipitasi aseton. Aktivitas enzim ditentukan dari jumlah asam urat yang terbentuk pada setiap fraksi aseton, sedangkan kadar protein dianalisis dengan metode Bradford. Hasil menunjukkan fraksi aseton 60-90% memberikan aktivitas spesifik tertinggi dengan kemurnian 29,190%. Enzim menunjukkan aktivitas optimum pada pH 7,5 dan suhu 33 °C, serta berat molekul sekitar 65 kDa. Uji inhibisi menunjukkan bahwa semakin tinggi konsentrasi allopurinol yang digunakan maka semakin besar persen penghambatan yang dihasilkan. Konsentrasi allopurinol 2 ppm memberikan persen inhibisi tertinggi yaitu 90,376%.
Xanthine oxidase (XO) enzymes play a role in the formation of uric acid and can be obtained from various sources, one of which is goat milk. This study aims to provide xanthine oxidase enzymes with known purity, characteristics (pH, temperature, and molecular weight), and to determine the effect of the inhibitor allopurinol on XO enzyme activity. Isolation was performed using NaCl, followed by partial purification through acetone precipitation. Enzyme activity was determined by the amount of uric acid formed in each acetone fraction, while protein content was analyzed using the Bradford method. The results showed that the 60-90% acetone fraction exhibited the highest specific activity with a purity of 29.190%. The enzyme exhibited optimal activity at pH 7.5 and 33 °C, with a molecular weight 65 kDa. Inhibition tests showed that higher concentrations of allopurinol resulted in greater inhibition percentages. A concentration of 2 ppm allopurinol yielded the highest inhibition percentage of 90.376%.