ABSTRACT
<p><b>OBJECTIVE</b>To purify mutacin produced from isolated Streptococcus mutans (S. mutans) strains in order to, contribute to molecular biological research of mutacin.</p><p><b>METHODS</b>The antibacterial activity of 80 isolated strains was tested by the stab culture technique against Streptococcus oralis ATCC 10557. The mutacin produced by strain 1G, was initially purified by solid-phase extraction (SPE) after crude extraction by chloroform. And then the active substances were purified by twice reversed-phase high performance liquid chromatography (RP-HPLC). The purified target peptide (mutacin) was collected and freeze-dried for further study.</p><p><b>RESULTS</b>The greatest active strain of these S. mutans isolates, the strain 1G was obtained. Roughly 15 microg crude mutacin was extracted from 200 mL liquid medium of this strain 1G. The purified mutacin through SPE and twice RP-HPLC was obtained.</p><p><b>CONCLUSION</b>It was much complex to separate and purify mutacin due to its small molecular mass, and extracting and purifying of mutacin may make an important contribution to the further research of mutacin.</p>