Expression of Human Epidermal Growth Factor in Escherichia coli by Intein Approach

Different approaches are used to express recombinant proteins without the requirement of post-translational modification in Escherichia coli (E. coli). Though E. coli may have a drawback in producing endotoxin, its short division time and high expression of the final product are significant in making use as a host to produce various recombinant proteins. Inteins have been discovered in multiples microorganisms in facilitating the expression of homologous proteins and it has been used as one of the crucial tools for the production of recombinant proteins due to its unique feature in auto-excising its fusion partner, which also known as exteins. In this communication, we employed a well-established gp41-1 mini-intein to facilitate the expression of epidermal growth factor (EGF). The study revealed that though the epidermal growth factor cannot be excised from the gp41-1 mini intein during the expression, it showed the capability of gp41-1 mini intein in processing intracellular expression of soluble EGF fusion protein. Different conditions for inducing the cleavage of exteins from inteins has been studied by many research groups, and reducing condition by using the DTT works well on the C-terminal cleavage of EGF from the gp41-1 mini intein. The final purified, different concentration of EGF was mixed with homemade aqueous cream and showed to be highly active in accelerating the healing rate of patients suffering from bedsores, diabetic foot ulcers and skin rupture.