Ephraim Katzir (1916–2009): The Architect of Immobilized Enzymes and Israeli Science
Ephraim Katzir was a rare polymath who bridged the gap between the microscopic world of protein chemistry and the macroscopic world of international statesmanship. As a biophysicist, he pioneered techniques that laid the foundation for the modern biotechnology industry. As a public figure, he served as the fourth President of the State of Israel, navigating the country through the aftermath of the Yom Kippur War.
1. Biography: From Kiev to the Presidency
Ephraim Katzir was born Ephraim Katchalski on May 16, 1916, in Kiev, then part of the Russian Empire. In 1925, his family immigrated to Mandatory Palestine, settling in Jerusalem.
Education and Early Career:
Katzir enrolled at the Hebrew University of Jerusalem, where he studied botany, zoology, and chemistry. He earned his Ph.D. in 1941, focusing on synthetic polymers of amino acids under the supervision of Max Frankel. During this period, he was also an active member of the Haganah (the Jewish paramilitary organization), where his scientific expertise was channeled into the development of explosives and propellants for the burgeoning state.
Academic Trajectory:
In 1948, following the establishment of the State of Israel, Katzir joined the newly formed Weizmann Institute of Science in Rehovot. He founded and headed the Department of Biophysics, a position he held for decades. In 1966, he became the first Chief Scientist of the Israel Defense Forces, establishing a model for scientific integration within government and security sectors.
Presidency (1973–1978):
In 1973, at the request of Prime Minister Golda Meir, he stood for the presidency. Upon taking office, he Hebraized his surname to Katzir. His term was defined by the trauma of the 1973 Yom Kippur War and the subsequent peace process with Egypt. He famously chose not to seek a second term in 1978, preferring to return to his laboratory benches.
2. Major Contributions: Modeling Life and Industrializing Biology
Katzir’s scientific legacy is defined by two revolutionary breakthroughs:
Synthetic Poly-amino Acids:
In the 1940s and 50s, the structure of proteins was a "black box." Katzir developed methods to create synthetic chains of single amino acids (poly-amino acids). By creating these simplified models, he allowed researchers to study the physical and chemical properties of proteins in a controlled environment. This work was instrumental in deciphering the genetic code and understanding how protein chains fold and interact.
Immobilized Enzymes:
Katzir’s most commercially significant contribution was the development of immobilized enzymes. Naturally, enzymes are soluble and difficult to recover after a chemical reaction. Katzir found ways to "tether" enzymes to insoluble carriers (like polymers or glass beads) without losing their catalytic activity.
- Significance: This allowed enzymes to be used repeatedly in industrial processes. This discovery is a cornerstone of modern biotechnology, used today in everything from the production of high-fructose corn syrup to the synthesis of semi-synthetic penicillins.
3. Notable Publications
Katzir authored hundreds of papers, but several stand out as foundational texts in biophysics:
- "Linear Polymers of L-Amino Acids" (1951, Advances in Protein Chemistry): This paper established the methodology for using synthetic models to understand complex proteins.
- "Water-Insoluble Derivatives of Enzymes, Antigens, and Antibodies" (1966, Annual Review of Biochemistry): A seminal work that detailed the immobilization of biological molecules, effectively launching a new branch of applied biochemistry.
- "Poly-α-Amino Acids" (1965, Science): A comprehensive review that summarized decades of work on synthetic peptides and their role as protein models.
4. Awards & Recognition
Katzir was one of the most decorated scientists of the 20th century:
- Israel Prize in Life Sciences (1959): Awarded alongside his brother, Aharon.
- The Japan Prize (1985): For his "pioneering contributions to the field of immobilized enzymes."
- Foreign Member of the Royal Society (1977): One of the highest honors in the UK scientific community.
- Member of the National Academy of Sciences (USA): Elected as a foreign associate in 1966.
- Honorary Doctorates: Received over a dozen honorary degrees from institutions including Oxford, Harvard, and ETH Zurich.
5. Impact & Legacy
Katzir’s impact is felt in two distinct spheres:
Industrial Biotechnology:
Every time a pharmaceutical company uses an enzymatic reactor to create a drug, they are using technology Katzir pioneered. His work turned biology into an engineering discipline, moving it from the petri dish to the industrial vat.
Scientific Infrastructure:
Katzir was the primary architect of Israel’s scientific policy. He advocated for the "Chief Scientist" system in government ministries, ensuring that policy decisions were informed by rigorous data. He also founded the Katzir Center at the Weizmann Institute, which continues to foster interdisciplinary research.
6. Collaborations
Katzir was a deeply collaborative researcher who mentored a generation of Israeli scientists:
- Aharon Katzir-Katchalsky: His older brother and a world-renowned physical chemist. The "Katchalski brothers" were the powerhouse of early Israeli science.
- Michael Sela: A long-time collaborator at the Weizmann Institute. Together, they worked on synthetic antigens, research that eventually led to the development of Copaxone, a leading treatment for multiple sclerosis.
- Meir Wilchek: Katzir worked closely with Wilchek on affinity chromatography, a method used to purify biological molecules that remains a standard laboratory technique worldwide.
7. Lesser-Known Facts
- The Lod Airport Massacre: In 1972, just a year before Ephraim became President, his brother Aharon was murdered by members of the Japanese Red Army during a terrorist attack at Lod (now Ben Gurion) Airport. This tragedy profoundly affected Ephraim’s transition into public life.
- The "Science Corps": During the 1948 Arab-Israeli War, Katzir was a commander in HEMED (the Science Corps). He was known for working in makeshift labs to create "Davidka" mortar shells and other essential munitions when the new state had almost no industrial military capacity.
- A Return to the Bench: After his presidency ended in 1978, he did something almost unheard of for a former head of state: he returned to full-time research and teaching. He even lived in the faculty housing at the Weizmann Institute, insisting on being treated as a professor rather than an "Excellency."
- Youth Science: He was a passionate advocate for science education and founded the Science-Oriented Youth program at the Weizmann Institute, which became a model for similar programs globally.