Purifacation And Characterization Of Superoxide Dismutase From Fungus Cordyceps Militaris

Superoxide dismutase (SOD) is a metal-containing enzyme which catalyzes the dismutation reaction of superoxide free radical anions and produces O₂ and H₂O₂. It has been found that it's relational with the organism anti-decrepit,anti-tumor, nutrition situations,immunity disease,the inflammation and radiation protection. Cordyceps militaris (L.) is the traditional valuable Chinese herbal medicine, it was reported that the pharmacody was concerned with the activity of SOD.The growth increment of cultured mycelia of Cordyceps militaris (L.)Link was influenced by liquid medium with different C/N ratio under different conditions of temperature and culture time. Also the cultivated conditions of Cordyceps militaris (L.) were studied.The results showed that the optimal C/N ratio was 50∶1, the 7th day was the logarithm stage for the mycelia growth, and the best culture temperature ranged from 23℃to 25℃.Dark culture was best for the growth of mycelia.In this research,the superoxide dismutase from Cordyceps militaris has been isolated by optimal experiment to study the effects of the optimum conditions of isolation. The results showed that the optimal isolating condition were that the ratio of the Cordyceps militaris to the phosphoric acid buffer solution was 1∶3 (m/V), the phosphoric acid buffer solution pH value was 7.73, the extractive time was 3h.The SOD was purified by method means were composed of ultrafiltration concentrating,the DEAE-FF ion exchange chromatotography (1.0×50) and then SephdexG100 gel chromatotography (1.5×50cm).The method presented the results that purification multiple was 4.09.The characters of SOD was researched. Following purification, we measured that the optimum reaction temperature of purified SOD is around 30℃,it had good heat stability(20～60℃) and the optimum pH is 7.8 and acid-base stability in pH7.0-8.0,in which he activity of SOD did not decline clearly.The lactose, sucrose, glucose, maltose was found not impact on the activity of SOD,but the organic acid effected the activity of SOD strongly.The enzyme was sensitive to H₂O₂, finally the Atomic Absorption spectrophotometers was used to measure and reveale that purified enzyme contained latom of copper and 2 zinc per subunit.