Abstract:Chlorella vulgaris was cultivated for five days under the stress of 60 μmol/L of Zn2+ (ZnCl2). After harvest by centrifugation, the algal cells were washed with EDTA and water, and were homogenized by a supersonic cell disintegrator. After centrifugation, the supernatant, a crude proteincontaining extract, was separated and purified with a gel filtration column (Sephadex G-75, 3.5 i.d.×80 cm) and a desalting gel filtration column (Sephadex G-25, 1.5 i.d. × 30 cm). The obtained Znbinding proteins were characterized with several analytical methods. Results showed that the molecular weight of the proteins measured with tricineSDS-PAGE was about 8.2 ku, and the cysteine content of the proteins was 15.4%. In addition, the characteristic ultraviolet spectrum of the proteins was found to be similar to that of the standard MTs from rabbit liver. Therefore, the Znbinding proteins were referred as metallothioneinlike (Zn-MT-like) proteins. Based on the agar hole pervasion method, the activities of antibacterial and antifungal of Zn-MT-like proteins were tested. The results showed that Zn-MT-like proteins strongly exhibited the antimicrobial activities against grampositive bacteria (including Staphylococcus aureus and Bacillus subtilus), Penicillium chrysogenum and Aspergillus niger, but was insensitive to Escherichia coli and brewer’s yeast. The diameters of inhibition zone for 1 mg/mL of Zn-MT-like protein were 13.2, 17.4, 7.2 and 9.8 mm for S. aureus, B. subtilus, P. chysogenum and A. niger, respectively. However, no anti-microbial activity was found for the standard Zn-MTs from rabbit liver. The antimicrobial activities of Zn-MT-like proteins from C. vulgaris may be helpful for the further comprehensive development and utilization of the alga.