How does dilution affect the conductivity, the propensity to aggregate and the biological activity of enzymes?

Abstract

The current theories do not provide a convincing explanation for many of the protein' manifestations in solution. Therefore, to shed some light on this critical question, the present work analyzed the effect of dilution on the ability of proteins to catalyze chemical reactions, the so-called biological activity. As models enzymes, laccase from Trametes versicolor and chicken egg white lysozyme were used.

The results show that the enzymes' specific biological activity increases on dilution. Three explanations for the intriguing observation were advanced and submitted to experimental scrutiny. Amongst the three hypotheses, only one was corroborated by experiments. According to this explanation, when dissolved in water, proteins reveal two populations: one biologically active whose relative occurrence increases on dilution and another which is not active and whose molecular proportion varies in the opposite direction.

Therefore, the reported experimental facts strongly support the chemical behaviour of the proteins in the solution. According to the herein-advocated concepts, they could undergo a dissociation process similar to that found in electrolyte chemistry.