Question

Give the purification scheme for isolation of Humulin from E. coli.

Hint:

Focus on both the source organism, and the different methods that need to be employed when working with intracellular proteins.

Answer 1

Fermentation Broth: Recombinant plasmid-carrying E. coli (encoding human insulin, "Humulin") is cultured in a fermenter. Cell Harvest and Lysis: Following fermentation, bacterial cells are harvested and lysed to liberate intracellular contents, including Humulin protein. Cell debris removal and protein solubilization: Cell debris is removed via centrifugation and filtration. Humulin protein requires solubilization using buffers for separation from other proteins. Chromatography: The solubilized protein mixture is passed through chromatographic columns for purification based on size, charge, or affinity. Refolding and purification: The protein undergoes purification and refolding to achieve its active state. Final Purification: The resultant product may undergo further purification steps to meet pharmaceutical standards.