Influence of Ultrasonic Wave on the Crystallization of Lysozyme

Due to the highly sensitivity of proteins to the crystallization conditions, a slight change in operating parameters might affect the outcome of the crystallization. In this study, the effects of ultrasonic wave on the crystallization of lysozyme were investigated by applying different levels of ultrasound during the purification process of lysozyme from the aqueous solutions of hen egg white through the solvent freeze out (SFO) technology. Tetragonal lysozyme crystals were obtained during the process, which were then verified by X-Ray Powder Diffraction (XRPD). The quality of lysozyme crystal (composition and purity, size and shape, enzyme activity) was measured using SDS-PAGE, polarized light microscopy and spectrophotometer, respectively. It was found that the purity and size of lysozyme crystal were affected significantly by ultrasonic wave, while the enzyme activity of lysozyme crystal weren’t. In addition, the influence mechanism of ultrasonic wave on lysozyme crystallization was discussed. The results obtained by this work will provide essential information for the purification of other proteins.