EFFECT OF POLYPHENOL OXIDASE PURIFIED FROM SWEET PEPPER (Capsicum annuum L.) IN AGGREGATION OF STRPTOCOCCUS MUTANS THAT CAUSE TOOTH DECAY

The present study was conducted to screen three parts (fruit , leaves, stem and seeds) to determine the polyphenol oxidase activity , the fruit part showed the highest specific activity and followed by leave and stem but the seeds reached less specific activity .when catechol was used as substrate. The study was also amid to determine the optimum condition for enzyme extraction . it used three method to extract enzyme to select the best. finally extraction by 0.1M sodium phosphate buffer ,pH 7.5 , and followed extract by acetone powder while decrease when extract by 0.1M potassium phosphate buffer The purification process included ammonium sulfate precipitation by saturation ratio 70%, ion exchange chromatography by using DEAE-cellulose and gel filtration chromatography on the Sepharose 6B column, The characterization studies revealed that the molecular weight of enzyme determined by Sepharose 6-B column was 38355 Da . The optimum pH for enzyme activity and stability were 7.5 and (7-8) respectively . The optimum temperatures for enzyme activity and stability were 30 C and (20-35)C, respectively . The effect of metal ions showed decrease in the activity of the enzyme with HgCl2 at 5mM and 10mM while increase in activity with CuSO4 and CaSO4,NaCl,FeCl3 at same concentration . The enzyme inhibition by ascorbic acid ,SDS,sodium azid and EDTA .but no effect activity when enzyme incubated with MgSO4,ZnSO4.