(1861–1947) British biochemist
Hopkins was the son of a bookseller and publisher and a distant cousin of the poet Gerard Manley Hopkins. He was born at Eastbourne and, after attending the City of London School, was apprenticed as a chemist in a commercial laboratory, where for three years he performed routine analyses. An inheritance in 1881 allowed him to study chemistry at the Royal School of Mines and at University College, London. His work there brought him to the attention of Thomas Stevenson, who offered Hopkins the post of assistant in his laboratory at Guy's Hospital. Feeling the need of more formal qualifications he began to work for a medical degree at Guy's in 1889, finally qualifying in 1894. In 1898 Hopkins moved to Cambridge, where he remained for the rest of his long life and not only served as professor of biochemistry (1914–43) but also established one of the great research institutions of the century.
In 1901 Hopkins made a major contribution to protein chemistry when he discovered a new amino acid, tryptophan. He went on to show its essential role in the diet, since mice fed on the protein zein, lacking tryptophan, died within a fortnight; the same diet with the amino acid added was life-supporting. This work initiated vast research programs in biochemical laboratories.
In 1906–07 Hopkins performed a classic series of experiments by which he became convinced that mice could not survive upon a mixture of basic foodstuffs alone. This ran against the prevailing orthodoxy, which supposed that as long as an animal received sufficient calories it would thrive. He began by feeding fat, starch, casein (or milk protein), and essential salts to mice, noting that they eventually ceased to grow. Addition of a small amount of milk, however, was sufficient to restart growth. It took several years of careful experiments before, in 1912, Hopkins was prepared to announce publicly that there was an unknown constituent of normal diets that was not represented in a synthetic diet of protein, pure carbohydrate, fats, and salts. Hopkins had in fact discovered what were soon to be called vitamins, and for this work he shared the 1929 Nobel Prize for physiology or medicine with Christiaan Eijkman.
At the same time Hopkins was working with Walter Fletcher on the chemistry of muscle contraction. In 1907 they provided the first clear proof that muscle contraction and the production of lactic acid are, as had long been suspected, causally connected. This discovery formed the basis for much of the later work done in this field. Hopkins later isolated the tripeptide glutathione, which is important as a hydrogen acceptor in a number of biochemical reactions.
In England Hopkins did more than anyone else to establish biochemistry as it is now practiced. He had to fight on many fronts to establish the discipline, since many claimed that the chemistry of life involved complex substances that defied ordinary chemical analysis. Instead he was able to demonstrate that it was a chemistry of simple substances undergoing complex reactions. Hopkins was knighted in 1925.
Subjects: Science and Mathematics — Contemporary History (Post 1945).