Axel Hugo Teodor Theorell was a pioneering Swedish biochemist born on July 6 1903 in Linköping Sweden and passed away on August 15 1982 in Stockholm. He obtained his medical degree from Karolinska Institutet in 1930 with a thesis on blood lipids and was appointed professor in physiological chemistry at the same institution. Early in his career he held positions at Uppsala University and worked with Otto Warburg at the Kaiser Wilhelm Institute in Berlin where he conducted foundational enzyme research. From 1937 until his retirement in 1970 he served as director of the biochemical department at the Nobel Medical Institute in Stockholm establishing it as a world center for enzymology.
Theorell was awarded the Nobel Prize in Physiology or Medicine in 1955 for his groundbreaking research on the nature and mode of action of oxidation enzymes that revolutionized understanding of cellular energy production. In 1932 he became the first scientist to isolate crystalline myoglobin an oxygen-carrying protein in muscle tissue providing critical insights into oxygen transport mechanisms. His 1935 isolation of the yellow enzyme demonstrated its composition of a coenzyme flavinmononucleotide and a colorless protein establishing the fundamental structure of oxidation enzymes. His subsequent research on cytochrome c elucidated the precise chemical linkage between the iron-bearing porphyrin portion and the apoenzyme while his work on alcohol dehydrogenase led to the development of sensitive blood tests for determining legal intoxication.
Theorell's discoveries fundamentally transformed the field of enzymology creating the modern understanding of how enzymes facilitate oxidation reactions in living cells and generate usable energy from nutrients. His research provided the foundation for numerous medical applications including standardized blood alcohol testing methods adopted by multiple governments and insights into metabolic processes relevant to disease research. He served as president of the Swedish Royal Academy of Science and the International Union of Biochemistry receiving honorary degrees from universities across Europe and the Americas. Recognized as one of the founders of modern enzymology and protein chemistry his work continues to influence biochemical research and medical diagnostics worldwide with his methods and conceptual frameworks remaining essential to the field.
