The most powerful technique for determining the structure of a chemical compound is x-ray crystallography. In this technique, a beam of x rays is focused on a crystal of a compound. The diffraction pattern produced enables chemists to determine the location of atoms within the crystals and hence deduce the molecular structure. It was Dorothy Hodgkin who pushed the limits of the technique to determine the structures of some biologically important molecules, including penicillin, vitamin B12, and insulin.
Born in Cairo in 1910 to English parents, Hodgkin became interested in chemistry by the age of ten. At thirteen, she attempted to analyze minerals she had brought back to England from the Sudan. Excelling in high school, in 1927 she was accepted at Oxford University, from which she graduated in 1931. Despite her obvious brilliance, Hodgkin was rejected for several positions. Fortunately, the famous crystallographer John Desmond Bernal at Cambridge University agreed to take her on as a researcher.
Hodgkin enjoyed the sparkling intellectual atmosphere at Cambridge, but financial hardship forced her to take a position as a tutor back at Oxford. It was there that she began her own research career in the lonely basement of the university museum. At that time, women were not permitted to join the chemistry club at Oxford University, so she was in effect barred from sharing in the intellectual life of her colleagues.
Throughout her career, Hodgkin selected projects that were always just beyond the currently accepted limits of feasibility, her initial research on the structure of cholesterol being one such example. In 1942 Hodgkin embarked on the first groundbreaking study of her career—the molecular structure of penicillin. Penicillin was the only effective antibiotic of the time and it had to be obtained from molds. If the structure could be determined, then it would be possible to devise a method of synthesizing it in chemical factories, reducing its cost and dramatically increasing its supply. Hodgkin and her research students determined the molecular structure of penicillin in 1945, in the process devising new crystallographic techniques.
Although Hodgkin had made major contributions to science, she still held the lowly rank of tutor. Deep in debt, she asked a senior professor to help her acquire a better position. With his help, she was appointed university lecturer in 1946. In 1948 she decided to take on the determination of vitamin B12's structure. This vitamin had been shown to prevent the disease of pernicious anemia but its chemical makeup remained unknown. With ninety-three atoms other than hydrogen, most chemists regarded the task of identifying its structure as impossible. Over the next six years, Hodgkin and her students toiled over the task. Their success in 1956 was the supreme triumph of her career.
Not until 1957 was Hodgkin promoted to university reader (approximately the equivalent of a full professor in North America). Even then, she was not provided with modern lab facilities until the following year. Despite her fame, it was the Royal Society , not Oxford University, that offered her the pinnacle of academic success, an endowed chair. Worldwide recognition of her work on the determination of the structures of biochemically important molecules came in 1964 when she was awarded the Nobel Prize in chemistry.
Hodgkin's third major project was determining the structure of the protein insulin. It was only technical advances in the 1960s that made the solution finally possible. When the results were published in 1969, the researchers were listed in alphabetical order, showing her willingness to share credit and her egalitarian attitude toward all research workers.
Hodgkin also had a very strong sense of social responsibility. After World War II, she became a member of the Science for Peace organization. Membership in this organization caused her to be denied a visa to attend a meeting in the United States during 1953. For the next twenty-seven years, to attend scientific meetings in the United States, she had to obtain a special entry permit from the U.S. attorney general. Only in 1990, when she was eighty years old, did the U.S. State Department relent and approve a visa application. Hodgkin formally retired in 1977, but she continued to be active in science until her death on July 30, 1994.
see also Cholesterol; Insulin; Penicillin.
Geoffrey W. Rayner-Canham
Farago, Peter (1977). "Interview with Dorothy Crowfoot Hodgkin." Journal of Chemical Education 54(4):214–216.
Ferry, Georgina (1998). Dorothy Hodgkin: A Life. London: Granta Publications.
Rayner-Canham, Marelene, and Rayner-Canham, Geoffrey (1998). Women in Chemistry: Their Changing Roles from Alchemical Times to the Mid-Twentieth Century. Washington, DC: American Chemical Society and the Chemical Heritage Foundation.
Sayre, Anne. "Remembering Dorothy Hodgkin." Available from <http://img.cryst.bbk.ac.uk/bca/obits>.