Studies on Precipitation Conditions of Phytase Protein from Transgenic Corn

In order to carry out further studies on enzymology properties of phytase protein expressed in transgenic corn seeds,we studied the relations between solubility of phytase and total protein and the saturation of ammonium sulfate with crude phytase extracted from transgenic corn seeds as material.The results showed that in the saturation range 0~60% of ammonium sulfate,the precipitated phytase only accounted for 1.85% of the total phytase in initial extraction,while the precipitated protein in the same saturation range accounted for 57% of the total protein in initial extraction.The specific activity of phytase was 0.44 U/mg.In the saturation ranging from 60%~80% of ammonium sulfate,the precipitated phytase and total protein accounted for 58% and 10% of the total in initial extraction,respectively.And the specific activity of phytase was 84.4 U/mg.In the saturation ranging from 80%~100% of ammonium sulfate,the yield of precipitated phytase accounted for 1.9% of the initial extraction.Therefore,the saturation ranging from 60%~80% of ammonium sulfate was set as the optimal condition to precipitate phytase.The specific activity of phytase obtained under this condition was 6.1 times higher than the crude extraction(13.8 U/mg).