Induction Time as an Instrument to Enhance Comprehension of Protein Crystallization

Abstract

Protein crystallization is a subject in which the commonplace “more an art than a science” still survives, and in which crystallization and crystallography are still synonyms. One of the major hindrances has been the lack of thermodynamic and kinetic parameters required for efficient crystallization design. In this article, induction times for porcine insulin and hen egg-white lysozyme were measured by absorbance at 320 nm at different levels of supersaturation, pH, and temperature, allowing determination of nucleation kinetics and interfacial tension. These parameters can help in the design and control of crystallization systems. Moreover, nucleation is explained on the basis of electrostatic interactions, and interfacial tension is related to the zeta potential of protein particles.