Daniel Koshland, biochemist, philanthropist and editor, believed strongly that science should be made accessible to everyone and that scientists had a public duty to explain how science has an impact on daily life and to show the relationships between science and public affairs.

Between 1985 and 1995 he was the editor of Science, the international weekly scientific journal, commuting regularly between the journal’s offices in Washington and the University of California at Berkeley, where he held a professorship of molecular and cell biology.

An enthusiastic, innovative editor, he published popular special editions, expanded the science news coverage of the journal and greatly improved the system of reviewing manuscripts. He was particularly keen that the journal should describe new developments in fields such as chemistry, immunology, medicine and neuroscience.

During his tenure he considerably improved the quality of Science so that it came to rival its British counterpart, the journal Nature, as the world’s top scientific magazine. Today Science is much the same periodical as it was when Koshland left it. He wrote editorials about the ethical questions that scientists have to deal with and campaigned for improved government funding for smaller-scale and adventurous research more interesting to the younger generation of scientists.

As a practising researcher Koshland made pioneering contributions to our understanding of enzymes and the chemistry of proteins. He is best known for proposing that enzymes changed shape as they reacted to other molecules – his “induced-fit theory” – which had important ramifications for the study of whole biological systems. He also performed important studies on bacteria, observing their ability to sense chemicals, and the signalling systems among cells. He later studied brain cells, using the brain chemical serotonin to investigate the retention and loss of memory.

Daniel Edward Koshland was born in Manhattan in 1920, and brought up in San Francisco. His father was president of the Levi Strauss Company, the jeans makers.

Koshland received his bachelor degree in chemistry from the University of California, Berkeley, in 1941. He then moved to the University of Chicago where he received his PhD in organic chemistry in 1949.

Between his undergraduate and postgraduate studies, during the war, he was recruited to work on the Manhattan Project at Chicago University and at the Oak Ridge National Laboratory, Tennessee, participating in the US effort to develop the atomic bomb.

He worked with the prominent American chemist Glenn Seaborg to isolate and purify the plutonium used as the fissile material in the first atomic bombs. Two plutonium bombs were fabricated during the war. One was tested in the New Mexico desert on July 16, 1945, and the other was dropped on Nagasaki on August 9, 1945.

When the war ended, Koshland went to Harvard for three years for postdoctoral research. In 1951 he moved to the Brookhaven National Laboratory, Long Island, where he was a senior biochemist. Between 1958 and 1965 he also worked at the Rockefeller University, New York.

In 1965 he returned to Berkeley as a professor of biochemistry and continued his research in biochemistry. He became head of the department of biology and, under a ten-year plan, reorganised the teaching and research in biology, emphasising interdisciplinary studies. New departments of plant biology, integrated biology and molecular and cell biology were established.

He remained at the University of California for the rest of his career. He was appointed Professor Emeritus in 1992 and continued his research until his death, publishing more than 100 scientific research papers during his career.

Koshland inherited a large fortune from his father (in 1997 Forbes magazine estimated that his wealth was $800 million) and used much of it to support science education. He was generous with his wealth. He gave about $23 million to Haverford College, Pennsylvania, to help to build a new science centre, which is named after his first wife, Marian Koshland. In 2004 he donated $25 million to found a science museum, also named after his first wife, at the National Academy of Sciences in Washington. He also donated $8 million to the Weizmann Institute of Science to fund postdoctoral scholarships at the Rehovot Institute, Israel.

Koshland received the US National Medal of Science in 1990 and an Albert Lasker Award for special achievement in medical science in 1998. He was a member of the US National Academy of Sciences and the American Academy of Arts and Sciences. He served as president of the American Society of Biological Chemists. He was a Guggenheim Fellow and a visiting Fellow at All Souls College, Oxford, a member of the American Philosophical Society, and an honorary member of the Japanese Biochemical Society and of the Royal Swedish Academy of Sciences. He was awarded honorary degrees from the University of Chicago, Carnegie Mellon University, Simon Fraser University and Mount Sinai Medical University, Israel.

Koshland had a very keen wit. He wrote about 200 editorials for Science, adopting the pseudonym Dr Noitall, a bumptious scientist, full of hubris.

His first wife died in 1997. His second wife, and one son and three daughters from his first marriage, survive him.

Daniel Koshland, biochemist, philanthropist and editor, was born on March 30, 1920. He died on July 23, 2007, aged 87