While Pauling continued to work toward the "general principles" of protein structure, others around the world were taking different approaches. William Astbury was taking and analyzing x-ray pictures of various fibers and other substances (including nucleic acid) at Leeds in England. He was joined there by A. J. P. Martin and Richard L. M. Synge (then a young graduate student), who were pioneering another technique, the use of paper chromotography to separate bits of proteins from one another, making it possible to tell how much of a given amino acid there might be in a particular protein. The technique would rapidly grow in importance as it was refined, becoming an invaluable part of protein research (and winning Martin and Synge a shared Nobel Prize in 1952). At the same time, at the Rockefeller Institute, Max Bergmann and others were moving ahead in determining the total amino acid composition of various proteins, making it possible to assign protein molecules a set chemical formula. Their work added more weight to the argument that proteins were, indeed, defined molecules, of a specific size and composition.

Although World War II had thrown many protein research projects off their tracks, a number of scientists, like Pauling, had managed to keep some studies going, often with government or foundation grants that could be placed under the general heading of wartime priorities. Many of these projects, like Pauling's, had to do with the composition of human blood.

This included a number of studies in Britain. Cambridge, for instance, had long been a global center for hemoglobin research. During the War Frederick Sanger was beginning his life's work there, picking apart the amino acid composition of proteins and figuring out ways to determine the sequence in which they linked to one another. This would eventually lead to the sequencing of insulin, the first protein to have its primary structure determined. Sanger earned his Ph.D. at Cambridge in 1943, and became a part of what would grow after the War into the world's most important gathering of protein researchers. He would be joined soon by Max Perutz, John Kendrew, Francis Crick, and other leaders in the field.

Cambridge and Leeds formed two centers for activity in Britain. But there was another. At the University of London, J. D. Bernal (although he himself was thrown into wartime duties, including helping plan the D-Day invasion) continued to maintain an interest in globular proteins. He managed to secure bridge funding, for instance, for his crystallographic associate, Dorothy Crowfoot Hodgkin, which allowed her to keep her equipment intact through the War and progress from the x-ray analysis of pepsin to work on a newly important molecule, penicillin.

The British were doing important work. But they continued to take a different approach from Pauling's. Many, like Hodgkin, Perutz, and Astbury, were becoming increasingly skilled at taking and interpreting x-ray photographs of protein crystals and fibers. Others, like Sanger, committed themselves to years of patiently taking apart proteins, piece by piece, to find out the order of amino acids that made them. They tended to focus on a single molecule, Sanger with insulin, Perutz with hemoglobin, Kendrew (eventually) with myoglobin, and so forth. They were not looking for general principles as Pauling was, or at least not primarily, but rather for the specific structures of real-world proteins. Pauling thought they had little chance of success.

He was wrong.