In 1901, the German chemist Emil Fischer synthesized the first pure dipeptide molecule; more than half a century later, most chemists were still using the same technique of adding and removing chemical accessories called “protecting groups” to the reactive parts of individual amino acids to direct organic synthesis in a controlled, linear, and stepwise fashion. The method, however, was arduous and not conducive to making large batches of more complex proteins.
In 1959, Bruce Merrifield, a Rockefeller chemist, devised a way to make peptide synthesis more efficient. Instead of working entirely in solution, Merrifield turned to a solid substrate. He attached growing chains of peptides to a resin support that could easily be removed by a simple wash procedure. This greatly increased protein yields, cut down the amount of time involved, and simplified the process of protein synthesis. “It was a real practical achievement,” says Alexander Mitchell, a synthetic chemist ...
