Zheng Wang

Publication Date


Document Type


First Advisor

Kresheck, Gordon C.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Chemistry


Phase partition; Globular proteins


The partitioning of several globular proteins was investigated in aqueous solutions of dodecyldimethylphosphine oxide (DodDPO). It was found that the partition coefficient, Kp, increased with the over-all concentration of the surfactant in the system. The concentration of proteins was also found to have an effect on KP. Generally, KP is smaller at higher protein concentrations. The experimental results of protein partitioning were compared with the values calculated by a theory based on an excluded volume model. Our findings suggest that the protein partitioning is not only affected by the particle size but that the interaction between protein and the surfactant micelles also plays an important role. Two ionic surfactants were also introduced into the system in order to investigate their effect on protein partitioning. It was observed that the cloud point of the system in the absence of protein was increased by the addition of the ionic surfactants. However, the effect of surfactant on the cloud point could be reversed by introducing a phospholipid, dimyristoylphosphatidylcholine, into the system. It was found that the protein partitioning was significantly affected by the electrostatic interaction. This makes it possible to control protein partition behavior by varying the size and charge of the different components and the pH value of the system.


Includes bibliographical references (pages [63]-65)


vi, 79 pages




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