Hugo Theorell – described how cells generate energy

“A fertile imagination. An undeviating and critical accuracy. An astonishing technical skill. All scientists possess some of these attributes. Very few have all. You are one of these few.”

Thus was the tribute paid to Hugo Theorell on becoming Karolinska Institutet’s first Nobel laureate in Physiology or Medicine in 1955. He was awarded the prize for “his discoveries concerning the nature and mode of action of oxidation enzymes”.

Enzymes are substances that can accelerate chemical reactions without themselves being consumed, making them the catalysts of the biological world. Virtually all reactions in the living cell are initiated and directed by enzymes.

Oxidation enzymes, the type of enzymes to which Hugo Theorell devoted most of his career, are essential to many vital biological processes, such as the ability of cells to employ oxygen in the generation of usable energy from nutrients.

Discovery made shortly after graduation

Hugo Theorell made his first groundbreaking discovery about oxidation enzymes in Berlin in 1935, a mere five years after earning his medical degree from Karolinska Institutet with a thesis on blood lipids.

While in Berlin, Theorell worked with biochemist Otto Warburg, a pioneer of biochemical research who received the Nobel Prize in Physiology or Medicine in 1931. Through the agency of his professor, Einar Hammarsten at KI, Theorell had been awarded a research grant by the Rockefeller Foundation in order to help study a yellow preparation of an oxidation enzyme from yeast using his self-developed electrophoresis machine.

Theorell succeeded in isolating a pure form of the enzyme and showing that it comprised two parts, a so-called coenzyme and a colourless protein, both of which are required for the enzyme to work.

Important work on iron atoms

Theorell returned to Karolinska Institutet in 1936 and was appointed professor and director of the biochemistry division of the newly established Medical Nobel Institute. A decade or so later, the division relocated to the new premises of the Nobel Institute on what is now Karolinska Institutet’s Solna campus.

Theorell and his colleagues explored how a variety of oxidation enzymes are constructed, how they operate and how they react to different conditions. The enzymes on which the group worked included cytochrome c, which is involved in cellular energy generation; peroxidases, which break down harmful hydrogen peroxide; and alcohol dehydrogenases, which break down ethanol.

His research provided important information on how the iron atoms present in many oxidation enzymes contribute to their function.

Early on in his career, Theorell also crystallised a pure form of the protein myoglobin, which acts as a key oxygen carrier in muscle cells, and explained how it transports oxygen from the blood to muscle.

Music was also a big part of his life

Hugo Theorell was born in 1903 in Linköping, and took up the violin as a child. Music would become an important part of his life and when not researching he was a busy chamber musician, performing with both professional ensembles and amateur fellow scientists.

Hugo Theorell died in 1982.