Study On Isolation, Purification And Properties Of Lysozyme Of Quail Egg White

In order to learn more about the properties of egg white lysozyme,CM Sepharose FF cation exchange column chromatography and Sephadex G-75 gel chromatography were used to purify quail egg white lysozyme. The results showed that there were very clear distinction among the peaks,and the desired effect of purification was achieved. In the process of purification, cation exchange column chromatography had the most obvious effect. It improved 25.9 times of the purity and removed the majority of hybrid protein. Finally,lysozyme activity reached 14821.5U/mg, the purity of the protein was improved 29.0 times, and the activity recovery was 38%.The PAGE,SDS-PAGE, temperature, pH and metal ions were used to study and identify characteristics of quail egg white lysozyme. Each electrophoresis showed a single band, indicated that the purity of lysozyme reached electrophoresis class, its molecular weight is about 16000Da. This lysozyme had lower activity at 10℃～20℃and 40℃～60℃,while the activity reached maximum at 30℃. This showed that 30℃was the optimum temperature for the lysozyme. At neutral environment(pH 6～7), the activity of lysozyme had strongest activity. At acidic(pH<6.0)and alkaline(pH>7.5)environment, The activity of the lysozyme reduced. Zn2+,Cu2+ could activate the lysozyme, but Mn2+,Ag+ inhibited the activity of the lysozyme, and Ba2+,Ca2+,Fe3+,Na+ had no significant impact on the activity.The antibacterial activities of lysozyme was researched in vitro, including inhibition spectrum, minimal inhibitory concentration and inhibition mechanism which was studied by transmission electron microscopy(TEM). The results showed that the lysozyme could resist the infection of Gram-positive bacteria, such as Staphylococcus aureus, Bacillus subtilis. And it may resist a part of gram-negative bacteria, such as Aeromonas hydrophila bacteria, Vibrio anguillarum. But E.coli, Yersinia Bacteriostasis could not be inhibited. The minimal inhibitory concentrations of the lysozyme on Staphylococcus aureus, Bacillus subtilis, Aeromonas hydrophila bacteria and Vibrio anguillarum were 125,250,500,500μg/mL respectively.Through the observation of TEM, the lysozyme enable uneven cytoplasm of Staphylococcus aureus, the cell wall became thinning and breakdown as well.