Cytotoxic Potential of Purified Arginine Deiminase from Streptococcus spp.

The results that presented in the study were based on collecting one hundred and ten clinical samples of oral cavity, burns and wounds. Primary and secondary diagnositic showed that 14 out of these isolates belonged to Streptococcus spp.. The ability of these isolates in arginine deiminase enzyme production was screened and the results showed that these isolates were arginine deiminase producers with variable degrees. It has been found that one of these isolates which were Streptococcus mitis S5 had the highest specific activity (0.184 U/mg protein), therefore it was chosen for further study. Results of the optimum conditions for arginine deaminase production reveal that the maximum arginine deaminase production was achieved after supplementation of the production medium (pH 7.5) with 1% maltose as carbon source, 1.2% tryptone as nitrogen source, 30mM as arginine concentration and incubated at 37°C for 18h. Under these conditions, ADI purified in three steps including; precipitation with 70% saturated ammonium sulphate, dialysis then ion exchange chromatography using DEAE- cellulose column and the last step was gel filtration chromatography throughout Sephadex G150 column. Specific activity of the purified enzyme was increased up to 18 U/mg with 5 folds of purification and 70.8 % enzyme recovery. [ABSTRACT FROM AUTHOR]