Question

Which of the following describes the final step in the laboratory synthesis of biologically active humulin from isolated chains?

Options

• Re-attaching the C peptide to the A and B chains using DNA ligase

• Treating the fusion proteins with reducing agents to break disulphide bridges

• Combining purified A and B chains in vitro under oxidising conditions to form disulphide bonds

• Culturing \(E.\ coli\) under anaerobic conditions to synthesize both chains together

Answer 1

After the fusion proteins are extracted, cleaved, and purified independently, the A and B chains are combined in vitro under oxidising conditions, which allows the formation of disulphide bonds to yield biologically active humulin.