Fully Active Insulin by Selective Formation of the Disulfide Bridges between a Sythetic A‐Chain and Natural B‐Chain

Directed formation of the three disulfide bridges in insulin is a decisive synthetic step. Only 10% of insulin is formed on random recombination of A‐ and B‐ chains (1:1). An A‐chain synthesized with selectively removable sulfur protecting groups on a polymeric carrier was allowed to react with a natural B‐chain. The yield of fully active insulin increases to 25%