Proteins were the main focus of Linderstrøm-Lang’s research, and they are among the most important building blocks of life. They drive the body’s chemical reactions, play a role in our immune system and transport vital substances, as when the protein haemoglobin carries oxygen in our bloodstream.

By the early 20th century, scientists knew that proteins were comprised of amino acids but not how they worked in living organisms. This was the question that Linderstrøm-Lang set out to answer as a young researcher.

From 1919, he was employed at the Carlsberg Research Laboratory under the chemist S. P. L. Sørensen (1868–1939), succeeding him as head of the chemistry department from 1939 and until his death, in 1959. During the 1920s, Linderstrøm-Lang began a systematic effort to study how proteins change their electrical charge depending on the local pH and environment. He developed precise methods for measuring these variations, which play a key role in explaining why some proteins fold in a stable manner, while others lose their structure when boiled, for example.

Linderstrøm-Lang picked up an interest in protein chemistry from his mentor, but while Sørensen studied chemical properties, Linderstrøm-Lang wanted to understand the structure and movements of proteins. One of his more significant contributions was an elegant method for following which hydrogen atoms in a protein are replaced and how fast. That gave protein researchers new ways of describing proteins, in particular their dynamics.

As research head, Linderstrøm-Lang created an open environment where physicists and chemists worked together and which attracted young researchers from all over the world. Among them was the American Christian B. Anfinsen (1916–1995), who was awarded the Nobel Prize in Chemistry in 1972 for his work on the folding of proteins, a field he had been inspired to study while in Copenhagen.

Linderstrøm-Lang’s contributions to society went far beyond his lab work. During World War II, he was active in the Resistance and used the Carlsberg Research Laboratory to hide resistance fighters. He also helped Jews escape to Sweden, including Niels Bohr (1885–1962) and his family, who had to go into hiding before they were able to flee. After the war, Linderstrøm-Lang was an outspoken voice on research policy, advocating international cooperation and independent basic research.

This brings us to the lecture in 1951, which was held at the acclaimed Stanford University in California.

At the event, Linderstrøm-Lang introduced a system that classified protein structures into primary, secondary and tertiary levels. The system has since become the standard in protein research. The system gave the field a precise language for describing protein structures, from the sequence of amino acids to three-dimensional form. It also highlighted the close link between a protein’s activity and its dynamics and 3D structure. To understand how a protein functions, the researcher thus needs to know both its shape and how it changes over time. This way of thinking had a profound impact and inspired many future researchers.

Linderstrøm-Lang’s research made proteins much more accessible. He gave researchers a common language and efficient methods for studying them, which enabled much deeper insight into the inner workings of life itself. His legacy has affected both modern biochemistry and the protein research we continue to build on today.

The chapter is written by Kristian Sjøgren.