| Metallothionein (MT) is a special cysteine-based protein transporting metals (such as copper, zinc) in animals, plants, and microorganisms. In this thesis, the production and antioxidative activity of MT transporting copper (Cu-MT) from yeast (Saccharomyces cerevisiae ) were investigated. A yeast mutant, N`-1, was screened from mutated strains using alternating UV irradiation and N-methyle-N`-nitro-soguanidine (NTG) treatment, and the Cu-MT productivity increased more than 3 fold based on the copper ion -binding activity of sulfhydryl (SH) groups. Further optimization of fementation conditions (CuCl2 as the inducer with a concentration of 1.0 mmol/L, activated for 2 days, added 1mL activated culture into 50mL culture media in a 250mL flask and induced in a rotate shaker (140r/min) at 30℃for 2 days), the production of Cu-MT increased 6 fold.The optimum conditions of Cu-MT extraction/purification from yeast culture and its antioxidative activity were studied. The results showed that the ultrasonic treatment of yeast culture under a power of 200W for 30 min in a ratio of 1:15 for sample to extraction buffer increased the activity of–SH group to 0.085 (7 fold) after further denaturalization at 80℃for 6min.After Cu-MT was separated and purified using Sephadex G-50 gel filter column and DEAE-cellulose anion exchange column, three subtypes were obtained, with a molecular weight of 9KDa, 9KDs, and 8KDa, respectively, analyzed by SDS-PAGE gel electrophoresis. Compared with Vc, it was found that its antioxidative activity in eliminating OH-·was more effective than that of Vc.
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