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Portrait of Arieh Warshel
Photo: Tomasz A. Wesolowski · CC BY-SA 3.0 via Wikimedia Commons

Nobel Prize in Chemistry · 2013

Arieh Warshel

Kibbutz-born chemist who taught computers to model how enzymes work by joining quantum and classical physics.

The Nobel citation: “for the development of multiscale models for complex chemical systems”
Born
November 20, 1940, Kibbutz Sde-Nahum, British Mandate of Palestine (now Israel)
Affiliation at the time
University of Southern California, USA

Chemistry prize

2013

Shared with 2 other laureates.

Age that year

73years

Born in 1940.

Sources cited

17

Fact-checked September 24, 2026.

  • He had no high-school matriculation certificate, so he studied for outside exams during army service, carrying physics books in his kitbag.
  • His early modeling programs ran on the Weizmann Institute's computer Golem, named after the creature of Jewish legend.
  • The Weizmann Institute denied him tenure. He says the paper later honored by the Nobel was discussed in that same promotion review.
  • He fought in the 1967 and 1973 wars as a communications officer. A bullet once pierced his helmet, leaving a scar on his right ear.
  • Most of his father's family was murdered in 1941 in Lachowicze (now Lyakhavichy, Belarus), including an aunt who had studied engineering at the Technion.

The breakthrough

Hybrid quantum-classical computer models of enzymes (QM/MM)

Before the 1970s, chemists who wanted to model molecules on a computer had to choose. Classical physics treats atoms like balls joined by springs. It is fast enough for huge molecules such as proteins, but it cannot show bonds breaking, so it cannot show a chemical reaction. Quantum physics can show reactions, but the math is so heavy that computers of the time could handle only small molecules.

Warshel helped find a way to use both at once. As a graduate student at the Weizmann Institute he built a general balls-and-springs program with his adviser Shneior Lifson and then with Michael Levitt. At Harvard, he and Martin Karplus published the first model in 1972 that gave some electrons a quantum treatment and the rest a classical one. In 1976, working with Levitt in Cambridge, England, he made the idea general and used it on lysozyme, an enzyme that cuts chains of sugar molecules. The few atoms where bonds break got full quantum physics; the rest of the protein and the water around it got simpler physics. Think of a map app that shows every street near you but only highways far away.

He then used such models to explain why enzymes speed up reactions so much. Their charged and polar groups are already lined up to steady the reaction, while in plain water the molecules must first turn into place, which costs energy.[2],[3],[4],[5],[11]

“I never wrote an important paper that was not rejected first.”
Arieh Warshel, Speaking to USC Dornsife News in 2021, when his autobiography came out, about the resistance his ideas met.[8]

What it meant for humanity

Enzymes run almost all of the chemistry inside living things, from breaking down food to reading genes. Knowing how they work matters for medicine, but the key steps happen in a fraction of a millisecond and are nearly impossible to watch directly. The models Warshel helped create let scientists run those steps on a computer instead.

Today this approach is standard. A 2009 review called combined quantum-classical (QM/MM) methods the method of choice for modeling reactions in biological molecules, and the 1976 Warshel-Levitt paper has more than 4,000 citations. The Nobel committee noted that the same tools help improve catalysts, drugs and solar cells. Warshel's own group used them to simulate the first light-triggered step of vision, to work out the first charge-moving steps of photosynthesis, and later to study molecular motors such as F1-ATPase.

In medicine, his methods are used to predict how drug molecules interact with their protein targets, so designers can rely less on blind trial and error. In his Nobel lecture he named drug resistance as a key frontier: his group has worked on predicting which mutations let HIV escape a drug while keeping the virus working, with the aim of designing drugs that are harder to escape.

The broader change is in how chemistry is done. The prize announcement said the computer is now as important to chemists as the test tube, with simulations and experiments checking each other.

  • A 2009 review in Angewandte Chemie called hybrid quantum-classical (QM/MM) methods the method of choice for modeling reactions in biological molecules.[14]
  • The 1976 Warshel-Levitt lysozyme paper, the first general QM/MM model of an enzyme reaction, has more than 4,100 citations in Crossref's records.[5],[12]
  • The Nobel committee noted that these methods help chemists optimize catalysts, drugs and solar cells.[4]
  • His methods are used to predict how medicines interact with their protein targets, part of computer-aided drug design.[7]
  • In his Nobel lecture he described work on predicting which HIV protease mutations let the virus resist drugs, aiming at medicines that are harder to escape.[6]
  • In 1975 he and Levitt simulated a small protein folding into a shape close to its natural one, using a simplified model that lumped each amino acid's atoms into larger units.[5],[13]

Impact in numbers

Warshel's contribution is a way of doing chemistry, not a single product, so this profile makes no numerical claim. Hybrid QM/MM models, and his electrostatic and simplified coarse-grained models, are now routine tools in chemistry, biochemistry and drug research; the 1976 paper alone has more than 4,100 citations. But the value of any drug, catalyst or solar material these tools helped design cannot be separated from experiments, other computer methods, faster hardware and the work of many other scientists, including his co-laureates. Any count of lives saved or dollars earned would be invented. What can be said is that questions about how enzymes and other biological machines work, which experiments alone could not settle, can now be asked and tested on a computer, and that Warshel spent five decades insisting this was possible before most of his field agreed.

Fundamental scienceHealthTechnology

No number is given here on purpose. Some contributions cannot be counted honestly, and we would rather describe them than invent a figure.

The double edge

No harms have been documented from Warshel's modeling methods, which are research tools. His career has, however, involved long and sharp scientific disputes. He has written that his key ideas were first called wrong, then trivial, then credited to others, and his clashes with journal referees became well known. In 2010 he and Shina Kamerlin challenged a then fast-growing idea that protein motions ('dynamics') help explain how enzymes speed up reactions, arguing that electrostatic preorganization accounts for it. These are arguments about science, not harms.

  • Minor

    Long disputes over enzyme catalysis

    Warshel's ideas met years of hostile peer review. He wrote that his results were first called incorrect, then trivial, then attributed to others. In 2010 he and Shina Kamerlin argued that no proposed role for protein motions in catalysis had been shown experimentally, and that electrostatic preorganization explains enzyme speed, a direct challenge to a popular view.[2],[7],[15]

Against the odds

Warshel was born in November 1940 on Kibbutz Sde Nahum, a young collective farm in the Beit She'an Valley of British-ruled Palestine that had been set up in 1937 as a 'tower and stockade' settlement. His parents had come from Poland. By leaving Europe they survived the Holocaust; many of their relatives did not. In 1941 most of his father's immediate family was murdered when the Nazis massacred the Jews of Lachowicze, a formerly Polish town now in Belarus. An aunt who had studied engineering at the Technion died there too, and his mother's mother and two sisters were also killed. Across Poland, 2.77 to 3 million Jews were murdered.

He did not face the persecution his relatives met in Europe. His own obstacles were war, family loss and academic rejection. The kibbutz did not prepare children for university, so he had no matriculation certificate; he studied during army service and passed the Technion's entrance exam. He fought in the 1967 and 1973 wars, and a bullet once pierced his helmet. He became the first in his family to graduate from college.

Then his science met resistance. The Weizmann Institute did not give him tenure, and in 1976 he moved to the University of Southern California. For years journals rejected his papers. Recognition came slowly, and then in full with the 2013 Nobel Prize.

  • 1941

    Family killed

    Most of his father's immediate family was murdered in 1941 in Lachowicze (Polish between the wars, now Lyakhavichy, Belarus), in a Nazi massacre of the town's Jews. His aunt Chana, a former Technion engineering student, was killed there; his mother's mother and two sisters also died in the Holocaust.[7],[16],[17]

  • —

    Other

    The socialist kibbutzim of his youth discouraged members from leaving farm work for university, so he had no matriculation certificate. He studied for external exams during army service and got into the Technion through its entrance exam.[2]

  • 1967

    War

    Fought in the Six-Day War as communications officer of a reserve tank battalion that helped take the Golan Heights.[2]

  • 1973

    War

    Fought on the Golan Heights again in the Yom Kippur War, which he called traumatic. At some point in his combat service a bullet pierced his helmet, leaving a scar on his right ear.[2],[7]

  • 1976

    Other

    Denied tenure by the Weizmann Institute, he left Israel for the University of Southern California, part of a much-discussed Israeli academic brain drain.[8],[10]

Jewish background

Both parents JewishIdentified as Jewish, secular

Warshel was born in 1940 to Tzvi Warshel and Rachel Spreicher, Jewish immigrants from Poland who met on Kibbutz Sde Nahum in British-ruled Palestine. Both families came from Poland, and his parents survived the Holocaust because they had moved to Palestine; many relatives who stayed were murdered. He grew up in the kibbutz children's house, served as an officer in the Israel Defense Forces, and holds Israeli and US citizenship. After nearly 40 years in the United States, he told Israel's Army Radio in 2013 that he still defines himself as Israeli.[2],[7],[9]

Key dates

  1. November 20, 1940

    Born on Kibbutz Sde Nahum in the Beit She'an Valley, British Mandate Palestine, the eldest of four sons.[1],[2],[7]

  2. August 1958

    Begins army service as a communications specialist with the Golani infantry brigade, later becoming an officer.[2]

  3. 1962

    Starts studying chemistry at the Technion in Haifa.[2]

  4. 1966

    Earns his BSc at the Technion, marries Tamar Fabrikant, and joins Shneior Lifson at the Weizmann Institute.[2],[7],[9]

  5. June 1967

    Fights in the Six-Day War as a communications officer in a reserve tank battalion.[2],[7]

  6. 1968

    Publishes the Consistent Force Field with Lifson, an early general balls-and-springs model of molecules.[5]

  7. 1969

    Completes his PhD at the Weizmann Institute of Science.[1],[2],[7]

  8. 1970

    Begins postdoctoral work with Martin Karplus at Harvard University.[2]

  9. 1972

    With Karplus, publishes the first model combining quantum and classical physics in one molecule.[5]

  10. October 1973

    Fights on the Golan Heights again in the Yom Kippur War.[2],[7]

  11. February 1976

    After the Weizmann Institute declines to give him tenure, joins the University of Southern California.[2],[8]

  12. May 1976

    With Michael Levitt, publishes the general QM/MM model of an enzyme reaction, using lysozyme.[5],[11],[12]

  13. October 9, 2013

    Awarded the Nobel Prize in Chemistry with Martin Karplus and Michael Levitt.[3]

  14. 2021

    Publishes his autobiography, From Kibbutz Fishponds to The Nobel Prize.[8]

Sources

  1. 1.Arieh Warshel - Facts · NobelPrize.org (Nobel Prize Outreach), 2013
  2. 2.Arieh Warshel - Biographical · NobelPrize.org (Nobel Foundation), 2013
  3. 3.The Nobel Prize in Chemistry 2013 - Press release · Royal Swedish Academy of Sciences via NobelPrize.org, 2013
  4. 4.Taking the experiment to cyberspace (Popular information, Nobel Prize in Chemistry 2013) · Royal Swedish Academy of Sciences via NobelPrize.org, 2013
  5. 5.Scientific Background: Development of multiscale models for complex chemical systems · Royal Swedish Academy of Sciences via NobelPrize.org, 2013
  6. 6.Multiscale modeling of biological functions: from enzymes to molecular machines (Nobel Lecture) · Angewandte Chemie International Edition (PubMed Central), 2014
  7. 7.A Nobel Victory · USC Dornsife College of Letters, Arts and Sciences, 2013
  8. 8.Nobel laureate reveals his odyssey from working the fishponds in a Kibbutz to reaching the pinnacle of science · USC Dornsife College of Letters, Arts and Sciences, 2021
  9. 9.3 Jewish professors -- two of them Israeli -- share 2013 Nobel Prize in chemistry · The Times of Israel, 2013
  10. 10.Israeli ex-pats' Nobel win highlights brain drain · Associated Press via Phys.org, 2013
  11. 11.Theoretical studies of enzymic reactions: dielectric, electrostatic and steric stabilization of the carbonium ion in the reaction of lysozyme (Warshel and Levitt, J Mol Biol 103:227-249) · PubMed (National Library of Medicine), 1976
  12. 12.Crossref metadata record and citation count for Warshel and Levitt (1976), J Mol Biol 103:227-249 · Crossref, 2026
  13. 13.Computer simulation of protein folding (Levitt and Warshel, Nature 253:694-698) · PubMed (National Library of Medicine), 1975
  14. 14.QM/MM methods for biomolecular systems (Senn and Thiel, Angew Chem Int Ed 48:1198-1229) · PubMed (National Library of Medicine), 2009
  15. 15.At the dawn of the 21st century: Is dynamics the missing link for understanding enzyme catalysis? (Kamerlin and Warshel, Proteins 78:1339-1375) · PubMed (National Library of Medicine), 2010
  16. 16.Jewish Losses during the Holocaust: By Country · United States Holocaust Memorial Museum, Holocaust Encyclopedia
  17. 17.Lyakhavichy · Wikipedia

Fact-checked on September 24, 2026 by a separate AI fact-checking pass that re-opened the sources, with 6 corrections made. How we check

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