Leong

Ms. Susanna Leong is a visiting PhD student from Cambridge University. Her PhD thesis is titled refolding of human alphafeto protein (AFP).

AFP is a tumour-associated embryonic molecule which has been linked to the development of illnesses such as liver and skin cancer, Down’s syndrome, open neural tube defects and suppression of the immune response. A more complete investigation of the physiological activities of this oncofetal protein has been severely limited by the lack of an appropriate source from which to obtain biologically active AFP in any substantial quantity. My research objective is to achieve a novel AFP refolding method that gives high refolded and biologically active AFP yield from the inclusion body, which is cost-effective in an industrial setting. To attain an optimized refolding yield, the AFP inclusion body must be purified from other proteins and cell contaminants. Hence, a critical part of this research will focus on maximizing the removal of remaining inclusion body contaminants following solubilisation, to present an essentially homogeneous purified protein ready for refolding. Different refolding methods for AFP renaturation will be screened, with the selected refolding method subsequently transferred to a scaleable unit. Chemical extraction techniques may be applied to establish an integrated and intensified process for AFP manufacture. Simulation and modeling tools will be used to give an estimate of the feasibility of the process. Refolding of AFP is also being studied from a molecular perspective (i.e. the effects of ligand binding and glycosylation on AFP foldability and stability are currently being investigated).