Chain, Ernst Boris (1906–1979)

German-born British biochemist who was awarded a Nobel Prize for Physiology or Medicine in 1945, together with Alexander Fleming and Howard Florey (Fleming for his discovery of the bactericidal effect of penicillin, and Chain and Florey for their isolation of penicillin and its development as an antibiotic drug). Chain also discovered penicillinase, an enzyme that destroys penicillin. Chain was knighted in 1969.

Born and educated in Berlin, Chain fled to Britain from the Nazis in 1933. He worked at Cambridge University 1933–35, and then with Florey at Oxford. In 1949 Chain was invited to the Istituto Superiore di Sanità in Rome; he stayed there as professor until 1961, when he returned to the UK as professor of biochemistry at Imperial College, London.

At Oxford, Chain initially investigated the observation first made by Fleming in 1924 that tears, nasal secretion, and egg white destroy bacteria. Chain showed that these substances contain an enzyme, lysozyme, which digests the outer cell wall of bacteria. In 1937 Chain found another observation of Fleming's, that the mould Penicillium notatum inhibits bacterial growth. In collaboration with Florey, Chain isolated and identified the antibacterial factor in the mould.

Chain then elucidated the chemical structure of crystalline penicillin, finding that there are four types, each differing in its relative elemental constituents.

Chain also studied snake venoms and found that the neurotoxic effect of these venoms is caused by their destroying an essential intracellular respiratory coenzyme.