Bulk crystallization of lysozyme

Abstract

Protein crystallization has mainly been interested in growing a few crystals in small growth cells for structure determination o f the macromolecules by X-ray diffraction. While bulk crystallization (so-called mass crystallization) is used industrially for recovery and purification of many organic and inorganic materials, it has had only minor application to proteins. Crystallization can isolate a specific protein in bulk from a complex extract. Since the rapid advance in biotechnology and the increase in industrial demand, many proteins are now synthesized on a large scale. Bulk crystallization should be considered as a technique for the recovery of a significant amount of pure protein. In this work, lysozyme was selected as the protein for investigation of crystal growth kinetics in bulk crystallization. The crystal growth kinetics of tetragonal lysozyme in bulk crystallization were measured and compared with the published data on the growth of single crystal lysozyme.Measurement of the bulk crystallization of lysozyme was performed in a 1 litre stirred seeded batch crystallizer immersed in a temperature controlled water bath. Tetragonal lysozyme was crystallized by salting-out with sodium chloride (NaCl) precipitant using a sodium acetate (NaAc) buffer solution. The effect of lysozyme supersaturation δ, temperature T and concentrations of salt X and buffer B in solution on the lysozyme crystal growth rate Gprd was found to be,Gprd = 2.2 x10-4 (δ - b)2.exp[(T - 22)/7.5]exp[3.3(5 -X)]exp(0.16 - 0.2B).where b is a solubility correction term. This correlation fitted 95% o f the measured data within +20%. ........