Campbell, Pressman, Pauling and the Binding of Antibodies

Drawings of the interaction between an antibody and azoprotein by Linus Pauling. 1940s.

Dan Campbell first collaborated with Linus Pauling on a fellowship at Caltech in 1940, during which time the duo tried to explain how antibodies are formed. At the time, Pauling believed that antibodies were proteins in-the-making that needed to bind to antigens in order to fold and complete their structure. If this principle was correct, Pauling thought, it might be possible to create artificial antibodies by simply denaturing proteins and allowing them to bind and refold in the presence of antigens.

Despite the fact that Campbell’s initial test results cast doubt on his collaborator’s theories, Pauling went ahead and published his ideas on how antibodies work, hoping that further research could support his paper. Thus began a lengthy study of antigen-antibody binding in which Pauling and Campbell attempted to develop a complete theory. Along the way, Dan Campbell’s research at Caltech would become very important to the Institute as well as to Pauling.

In 1943 a Caltech research fellow named David Pressman agreed to join Campbell and Pauling in their study of immunology. Starting with work that had previously been published, Pressman, Pauling and Campbell refocused their studies to explain how antigens and antibodies bind, a change in focus from Campbell and Pauling’s earlier inquiries into how antibodies and antigens are formed. The decision to focus on previous research was made after Pauling had mistakenly announced that antibodies had successfully been synthesized at the Gates and Crellin Laboratories. As it turned out, attempts to create synthetic antibodies using Pauling’s proposed methods were completely unsuccessful. Pauling thus decided to start from scratch by developing a theory of antigen-antibody binding, which he would use to further investigate the chemistry of this interaction.

In July 1943, the three men published “The Nature of the Forces Between Antigen and Antibody and of the Precipitation Reaction,” appearing in the journal Physiological Reviews. The paper attempted to make more educated predictions about antigen-antibody binding.  In doing so, the article begins by referencing the concept of structural complementarity, which posits that antigen-antibody binding is driven by the close complementary physical shapes of the two molecules, which fit together like two adjoining pieces in a jigsaw puzzle. Commonly referred to as “the lock and key mechanism,” this idea was developed in the early 1930s, and served as Pauling and Campbell’s starting point in their initial investigations.

The 1943 study also drew from outside theories, such as the framework theory of precipitation, to suggest that antigen-antibody binding results in the formation of a precipitate; that is, that the two structures react to form an insoluble compound. Using these points as their foundation, the three researchers developed a new theory of antigen-antibody binding.

Pauling and Campbell, 1943.

Pauling and Campbell, 1943.

Campbell, Pressman and Pauling’s breakthrough came by way of their proposal that structural complementarity is an especially important feature for reactions that depend on Van der Waals forces. Van der Waals forces are weak forces of attraction that bind together molecules located in close proximity to one another. The Caltech researchers believed that the close complementary geometry of antibodies and antigens was significant enough to enable these molecules to fit together using the weak Van der Waals attraction as a binding force. In other words, the summation of Van der Waals forces present along the binding site of an antibody worked to bind it to its antigen, specifically because the shapes of antibodies and antigens complimented each other so closely. This theory explained much of what had been observed by immunologists across the discipline in multiple investigations of antigen-antibody reactions.

From here, the three researchers also asserted that two propositions placed forth in Pauling’s 1940 paper should still be considered for further study: the multivalence of antigen-antibody interactions and the probability of hydrogen bonds acting between the two molecules. The trio also concluded that the antigen-antibody mechanism would require at least two supplementary types of forces: Coulomb attraction and polar attraction.

Of the conclusions published by Campbell, Pressman and Pauling in 1943, the multivalence of antigen-antibody interactions and the three proposed forces (Van der Waals, Coulomb and polar) between the two molecules are still considered to be contributing factors to the functioning of the human immune system. With this publication, Campbell, Pauling and Pressman also showed that the immune system relies heavily on both structural and chemical features to carry out its processes.

The important conclusions derived from research conducted by Campbell, Pauling and others established Caltech as a leader in the field of immunology. Over the years that followed, Campbell and Pauling continued to develop their theory of antibody formation, which remained widely accepted until the 1950s. Even when the duo’s work began to be disproven by findings in the genetics field, the understanding of antigen-antibody interactions suggested by research done at Caltech remained undisputed.

Dan Campbell and Linus Pauling went on to publish more than twenty articles relating to immunology, exchanging ideas on the topic until the end of Pauling’s tenure at Caltech in the early 1960s. The attention that their work brought to the Gates and Crellin Laboratories at Caltech prompted the creation of a separate department, one that was entirely dedicated to immunochemistry. (The first of its kind on the west coast.)

For thirty years, Campbell headed Caltech’s immunochemical research and his fame as an immunologist grew to the point where, in 1972, he was named president of the American Association of Immunologists. Two years later, in 1974, Campbell passed away at the age of 67, the victim of a heart attack.  Over the course of his career, he published more than 200 papers as well as several books, and he served on editorial boards of four scientific journals related to immunology.


Rebecca Mertens, Resident Scholar

Rebecca Mertens

Rebecca Mertens

Rebecca Mertens of Bielefeld University, located in northwest Germany, is the latest visitor to complete a term as Resident Scholar in the Oregon State University Libraries Special Collections and Archives Research Center.  A Ph.D. candidate in the philosophy and history of science, Mertens spent a month stateside, visiting both the OSU Libraries as well as the Caltech Archives.

During her stay she braved both a major (and unusual) snow event in Corvallis as well as torrential rains in southern California.  Despite these obstacles, Mertens enjoyed a fruitful visit to the west coast as she pursued her research on Linus Pauling’s contributions to the lock-and-key model of biological specificity and the influence that this model imparted upon the sweep of modern biochemistry.

The conditions that awaited Mertens upon her arrival at OSU.

The conditions that awaited Mertens upon her arrival at OSU.

An outgrowth of his research on antibodies and antigens, Linus Pauling’s work on biological specificity comprised a major contribution to contemporary thinking on biochemical topics.  Pauling biographer Thomas Hager gives us this primer on what is meant by by the term, “biological specificity.”

Pauling demonstrated that the precise binding of antigen to antibody was accomplished not by typical chemical means – that is, through covalent or ionic bonds — but solely through shape. Antibodies recognized and bound to antigens because one fit the other, as a glove fits a hand. Their shapes were complementary. When the fit was tight, the surfaces of antibody and antigen came into very close contact, making possible the formation of many weak links that operated at close quarters and were considered relatively unimportant in traditional chemistry — van der Waals’ forces, hydrogen bonds, and so forth. To work, the fit had to be incredibly precise. Even a single atom out of place could significantly affect the binding.

In her Resident Scholar presentation, Mertens described the thrust of her research, which focuses on how one should interpret the contributions that Pauling made in this particular arena.

In the course of his research on antibodies, Linus Pauling postulated that the complementary structure of two molecules or two parts of a molecule determined the specificity of reactions in the living organism. However, the idea that molecular complementarity and biological specificity are deeply connected was already mentioned by Emil Fischer at the end of the 19th century. Thus, Pauling’s novel contribution was not the initial articulation of the model, but rather his emphasis on the importance of molecular complementarity for all biological phenomena.

Through examination of the Ava Helen and Linus Pauling Papers, as well as the institutional records held at Caltech, Mertens is pursuing the idea that “Pauling’s interdisciplinary reputation, his public presence and his engagement in the organization of scientific institutions led to the popularity of the lock-and-key model and to its standardization in the second half of the twentieth century.”  These forces of Pauling’s status and personality in turn made an impact on questions of “financial support, networking and science popularization within the administration of scientific projects.”


Beyond uncovering and detailing the history of Pauling’s role in the development of the lock-and-key model, Mertens is also using her research to “suggest an approach to the study of analogical models that considers social and political factors on successful model usage…[and] the formation and consolidation of model-based research programs.” Mertens returned to Germany with a large volume of content to sift through and absorb as she continues to develop her thinking on these issues.

Now entering its seventh year, the Resident Scholar Program at OSU Libraries provides research stipends of up to $2,500 to support work conducted in the Special Collections and Archives Research Center.  Applications for the 2014 class of scholars are being accepted now – the deadline for entry is April 30, 2014.  For more details, please see the program homepage.

The End of Artificial Antibodies

Illustration of bivalent antibodies attaching to complementary antigen molecules. Image extracted from a glass plate display, “Pictures of Antibodies,” prepared for the First International Poliomyelitis Conference, New York. The caption accompanying this image reads: “In vitro or in vivo bivalent antibodies may become attached to complementary portions of antigen molcules.”

[Part 3 of 3]

Though highly controversial, Linus Pauling’s claim that he had created artificial antibodies gave him a boost in funding. Many of his backers realized that if Pauling was correct he had just revolutionized modern medicine and they were just as eager as he was for his project to succeed. Since he now had more money, Pauling hoped he could expand his staff, though the war greatly prohibited this effort. Pauling lamented:

Unfortunately the amount of war work which is being done now here is so great that the usual seminars and informal discussions of science have decreased somewhat in number, but still a good bit of work in pure science is being carried on.

To help remedy this situation, Pauling corresponded frequently with William C. Boyd of Boston University’s School of Medicine, trying to persuade him to transfer to Caltech over the summer. Boyd refused, stating that he had too many other medical defense projects, though suggesting that “perhaps it will not be too late when the war is over, unless it goes on for 10 years or more, as some pessimistic writers predict.” Pauling also failed to hire two other well-known researchers, Henry F. Treffers, and A.M. Pappenheimer. Both declined because he was only able to offer a one year position. Indeed, from 1942-1943, Pauling actively tried to find staff for his lab, offering a $3,500 one-year position and draft deference. Despite this, most of the competent researchers he wanted were otherwise employed doing war work. He was able to hire Leland H. Pence in December of 1942, and in 1945 Frank Johnson visited from Princeton and worked at the lab in Caltech a bit. These individuals were, however, the exceptions, and Pauling was generally unsuccessful with his offers of employment.

Pauling was also facing other staff issues that were relics of the era. Among his group were two employees who were born and raised in the United States, but whose families were Japanese, Carol Ikeda and Miyoshi Ikawa. All too cognizant of the forthcoming policy of internment, Pauling began corresponding with Michael Heidelberg of Columbia University, hoping that he could temporarily trade employees as a method of getting Ikeda, at least, to a less hostile location. The plan did not work out, and Heidelberger ended one of his letters to Pauling bemoaning the fact that “…unfortunately a lot of wholly patriotic people are going to suffer.” Pauling was eventually able to get both Ikeda and Ikawa into graduate programs, though doing so took a substantial amount of work.

Dan Campbell and Linus Pauling, 1943.

Even though William Boyd had refused a job, he and Pauling continued to correspond frequently. Boyd was critical of Pauling’s theories on antibodies, warning his colleague that “preconceived notions evidently play a big role in the field [of immunochemistry.]” Boyd told Pauling to be careful with his research and his declarations, as he had often made arguments that he felt infallible only to have his colleagues inform him that they were unconvinced.

In August 1942, five months after issuing his controversial press release, Pauling finally published his research on artificial antibodies in an article titled “The Manufacture of Antibodies in vitro,” which appeared in the Journal of Experimental Medicine. As with the press release, Pauling’s paper was somewhat lacking in detail and many scientists found it hard to replicate his experiments. Those who did, such as Pauling’s valued colleague Karl Landsteiner, were unable to obtain the same results that Pauling had reported. Despite this, Pauling remained convinced that his research was valid and worth pursuing. However, Pauling’s collaborator Dan Campbell seemed to be the only one who could successfully produce the antibodies, and even those were weak and ineffective.

In early 1943 the Rockefeller Foundation assigned Frank Blair Hanson to assume some of the work that Warren Weaver had been conducting, and right away it was clear that Hanson was notably “less entranced than Weaver with Pauling’s work.” Despite the fact that he agreed to continue funding Pauling’s artificial antibody research, he was skeptical of its worth and began polling immunologists across the country to that end. They did not respond favorably – even Landsteiner believed that there was a less than 50% chance that Pauling had actually created artificial antibodies. As a result of these lackluster opinions, Hanson cut Pauling’s funding by half.

Pauling proceeded nonetheless, his enthusiasm still strong. His next move was to submit a patent application, “Process of Producing Antibodies.” The response that he received was not what he wanted to hear:

The claims are again rejected for lack of utility as no evidence has been presented to show that the antibodies alleged to be produced by the claimed have any utility at all… The claims are rejected as being too broad, functional, and indefinite…the claims are rejected for lack of invention…all the claims are rejected.

Pauling was disheartened by this response but still confident that he could salvage the project. However, shortly afterward he received a letter from the Rockefeller Foundation informing him that they did not approve of researchers using their funds to apply for medical patents. Because of the letter, and the general ineffectiveness of the research, Pauling opted not to pursue his patent application any further.

Illustration of the antibody-antigen framework. The caption accompanying this image reads: “…[An] antibody-antigen framework which may precipitate from a solution or be taken up by phagocytic cells.”

As 1943 progressed, Pauling continued to piece together a better understanding of how antibodies adhere to antigens. Later that year, he and Campbell published a paper in Physiological Review which further elaborated on their idea that shape was the primary determinant of antibody functions. They wrote that while many of their colleagues at other institutions felt that antibody formation adhered to a “lattice theory,” they did not, because their research showed that the structures created by antibody/antigen precipitation were not regular enough. Instead, they coined the phrase “framework theory” to describe their idea.

By the winter of 1943-1944, Pauling had at last concluded that the artificial antibody research was going nowhere. This was a difficult admission for Pauling because, despite the fact that progress in the research was still slow, he was convinced that he could make it work if given more time. Unfortunately for him, the war effort demanded quicker results and actively prohibited greater focus on antibodies. In the end, he decided to abandon the artificial antibodies research. Pauling never retracted his support for the work, though many years later Dan Campbell admitted that a laboratory technician had “shaded” the results to fit what he thought Pauling wanted to see.

The failure of the artificial antibodies project allowed Pauling to move on to more productive lines of research. He continued to build his ideas on how exactly antibodies function, and by 1945 he was able to prove that shape was indeed what caused antibodies to adhere to antigens. In Pauling’s description, the antibodies would fit to the antigens like a glove, at which point they adhered, not due to orthodox chemical bonds, but because of another weak, poorly understood force.

The force that causes antibodies to bind with antigens is called the van der Waal’s force. It is a very weak, almost imperceptible subatomic bond between two molecules existing in extremely close proximity. Historically, due to their weakness, van der Waal’s forces had been ignored as viable components of biochemical reactions. However, Pauling was able to show that the extremely tight fit between antibodies and antigens exposed a large surface area across which the van der Waal’s force could become a factor. The fit had to be precise, as even one or two atoms being out of place would effectively break the hold that the van der Waal’s force put into place. This concept, known variously as molecular complementarity or biological specificity, cast a great deal of light on a central mystery of molecular biology. With it, Pauling was additionally able to confirm his earlier hypothesis that antibodies are bivalent.

As World War II drew to a close, Pauling shifted his focus away from antibodies and back towards a more general study of the shape, creation, and function of proteins. Pauling’s focus on proteins was long lived, stretching at least twenty-five years from 1933-1958. His foray into antibodies was notably shorter, a nine-year interlude from 1936-1945. Yet in this time, he had managed to dramatically impact immunochemistry with his discovery that antibodies are bivalent and his insights into how they work. These accomplishments are made even more impressive when considering that Pauling was neither an immunochemist nor an immunobiologist by trade. As was so often the case during his life, he threw himself into the challenge with characteristic enthusiasm, and managed to make major contributions to the field.

Linus Pauling and the Structure of Proteins: A Documentary History


Today is Linus Pauling’s birthday – he would have been 112 years old.  Every year on February 28th we try to do something special and this time around we’re pleased to announce a project about which we’re all very excited: the sixth in our series of Pauling documentary history websites.

Launched today, Linus Pauling and the Structure of Proteins is the both latest in the documentary history series and our first since 2010’s The Scientific War Work of Linus C. Pauling. (we’ve been a little busy these past few years)  Like Pauling’s program of proteins research, the new website is sprawling and multi-faceted.  It features well over 200 letters and manuscripts, as well as the usual array of photographs, papers, audio and video that users of our sites have come to expect.  A total of more than 400 primary source materials illustrate and provide depth to the site’s 45-page Narrative, which was written by Pauling biographer Thomas Hager.


Warren Weaver, 1967.

That narrative tells a remarkable story that was central to many of the twentieth century’s great breakthroughs in molecular biology.  Readers will, for example, learn much of Pauling’s many interactions with Warren Weaver and the Rockefeller Foundation, the organization whose interest in the “science of life” helped prompt Pauling away from his early successes on the structure of crystals in favor of investigations into biological topics.

So too will users learn about Pauling’s sometimes caustic confrontations with Dorothy Wrinch, whose cyclol theory of protein structure was a source of intense objection for Pauling and his colleague, Carl Niemann.  Speaking of colleagues, the website also delves into the fruitful collaboration enjoyed between Pauling and his Caltech co-worker, Robert Corey.  The controversy surrounding Pauling’s interactions with another associate, Herman Branson, are also explored on the proteins website.

Linus Pauling shaking hands with Peter Lehman in front of two models of the alpha-helix. 1950s.

Linus Pauling shaking hands with Peter Lehman in front of two models of the alpha-helix. 1950s.

Much is known about Pauling’s famously lost “race for DNA,” contested with Jim Watson, Francis Crick and a handful of others in the UK.  Less storied is the long running competition between Pauling’s laboratory and an array of British proteins researchers, waged several years before Watson and Crick’s breakthrough.  That triumph, the double helix, was inspired by Pauling’s alpha helix, discovered one day when Linus lay sick in bed, bored and restless as he fought off a cold. (This was before the vitamin C days, of course.)

Illustration of the antibody-antigen framework, 1948.

Illustration of the antibody-antigen framework, 1948.

Many more discoveries lie in waiting for those interested in the history of molecular biology: the invention of the ultracentrifuge by The Svedberg; Pauling’s long dalliance with a theory of antibodies; his hugely important concept of biological specificity; and the contested notion of coiled-coils, an episode that once again pit Pauling versus Francis Crick.

Linus Pauling and the Structure of Proteins constitutes a major addition to the Pauling canon. It is an enormously rich resource that will suit the needs of many types of researchers, students and educators. It is, in short, a fitting birthday present for history’s only recipient of two unshared Nobel Prizes.

Happy birthday, Dr. Pauling!


The Medical Research of Linus Pauling

By Tom Hager

[Ed Note:  In October 2010, Pauling biographer Tom Hager delivered a talk sponsored by the Oregon Health Sciences University which detailed and discussed the various contributions that Linus Pauling made to the medical sciences, including the controversy over his strong interest in orthomolecular medicine.   With the author’s permission, excerpts of this talk are being presented on the Pauling Blog over the next three posts.  The full text of Hager’s OHSU lecture is available here.  Those with an interest in learning more about Hager’s work, including his latest research on food issues and world hunger, are encouraged to visit his blog at]

[Part 1 of 3]

Oil portrait of Linus Pauling, featuring a model of the alpha-helix in the foreground. 1951. Portrait by Leon Tadrick.

By 1939, at the age of 38, Linus Pauling was a full professor and head of the chemistry division at Caltech, as well as the father of four children (three sons, Linus, Jr., Peter, and Crellin; and a daughter, Linda).

He was also beginning to turn his considerable talents toward understanding the complicated molecules inside the human body. He started with proteins.

The Molecules of Life

Determining the structure of proteins at this time was a gigantic problem. Most were difficult to purify, easily degraded, and hard to characterize. Proteins appeared to be not only gigantic, comprising hundreds or thousands of atoms – much too large to solve directly with x-ray crystallography – but also relatively fragile, losing their function (denaturing) after even slight heating or mechanical disturbance. No one at the time was even sure that they were distinct molecules – one popular theory held that proteins formed amorphous colloids, gels that did not lend themselves to molecular study.

Studying them at the molecular level seemed an impossible task with the tools available in the late 1930s. But Pauling took on the challenge. He started with the building blocks of proteins, the amino acids, and directed his growing lab team toward pinning down their precise structures. Then he set himself to figuring out how they formed protein molecules, often building models out of wood, wire, and paper.

He based his approach in part on the ideas of the German biochemist Emil Fischer. Like Fischer, Pauling came to believe that proteins were long molecular chains of amino acids linked end-to-end. Working with Alfred Mirsky in the mid-1930s, Pauling discovered that the denaturing of proteins resulted from breaking weak bonds, called hydrogen bonds, that pinned these chains into specific shapes. Between the early 1930s and early 1950s he made a string of important discoveries about hemoglobin, antibodies (including the most sophisticated work at the time into the structural relationship between antibody and antigen), enzymes, and other proteins.

Foldable paper model of the alpha-helix protein structure published in the Japanese journal Chemical Field, 1954.

In May 1951, he put everything he knew into a celebrated series of seven papers detailing the structures of a number of proteins at the level of individual atoms, including the structure of the single most important basic form of protein, the alpha helix (a hydrogen-bonded helical chain that is a structural component of almost every protein). It was an astounding breakthrough, and it opened the door for an understanding of biology at the molecular level. Within two years, Watson and Crick had used his approach to decipher the structure of DNA.

Biological Specificity

But structure was not everything. Pauling realized that life resulted not from individual molecules, but from the interactions between them. How did organisms make offspring that carried their specific characteristics? How did enzymes recognize and bind precisely to specific substrate molecules? How did antibodies recognize and bind to specific antigens? How did proteins, these flexible, delicate, complex molecules, have the exquisite ability to recognize and interact with target molecules?

It all fell under the heading of biological specificity at the molecular level. Pauling directed much of his attention here during through the 1940s, performing a great deal of careful work on the binding of antigens to antibodies.

Drawings of antibodies and antigens made by Linus Pauling in the 1940s.

His findings were surprising. Pauling demonstrated that the precise binding of antigen to antibody was accomplished not by typical chemical means – that is, through covalent or ionic bonds — but solely through shape. Antibodies recognized and bound to antigens because one fit the other, as a glove fits a hand. Their shapes were complementary. When the fit was tight, the surfaces of antibody and antigen came into very close contact, making possible the formation of many weak links that operated at close quarters and were considered relatively unimportant in traditional chemistry — van der Waals’ forces, hydrogen bonds, and so forth. To work, the fit had to be incredibly precise. Even a single atom out of place could significantly affect the binding.

Having demonstrated the importance of complementary structure with antibodies, Pauling extended his idea to other biological systems, including the interaction of enzymes with substrates, odors with olfactory receptors, and to the possibility of complementary structure in genes.

Pauling’s idea that biological specificity was due in great part to complementary “fitting” of large molecules to one another proved to be essential in the development of molecular biology. His research now formed a coherent arc, from his early work on the chemical bond as a determinant of molecular structure, through the structures of large molecules (first inorganic substances, then biomolecules), to the interactions between large biomolecules.

He carried out much of this research during World War II, when he also worked on synthetic plasma substitutes and a fruitless search for ways to produce artificial antibodies.

He had already earned a place among the nation’s leading researchers in the medical applications of chemistry. But his greatest triumph was still to come.

Sickle-Cell Anemia

Toward the end of World War II, Pauling’s reputation was great enough to earn him an invitation to join a national committee that was brainstorming the best structures for postwar medical research. This committee’s work led to the foundation of the National Institutes of Health.

Pauling was the only non-physician asked to join the committee.

At a dinner with other members one night, talk turned to a rare blood disorder called sickle-cell anemia. One of his dinner companions described how red blood cells in the victims were twisted into sickle shapes instead of discs. The distortion appeared to hinder the blood cells’ transport through capillaries, resulting in joint pain, blood clots, and death. The disease primarily affected Africans and African Americans. What caught Pauling’s attention most, however, was one odd fact: Sickled cells appeared most often in venous blood, rather than in the more oxygenated blood found in the arteries.

Pastel drawing of sickled Hemoglobin cells, 1964. Drawing by Roger Hayward.

He thought about this during the next few days. From his previous work with blood, he knew that red cells were little more than bags stuffed with hemoglobin. He had also shown that hemoglobin changed its shape slightly when it was oxygenated. If the red cells were changing shape, perhaps it was because the hemoglobin was altered in some way. What if the hemoglobin molecules in sickle-cell patients were changed in some way that made them clump, stick to one another, as antigens stick to antibodies? Perhaps something had changed that made the hemoglobin molecules complementary in shape. Perhaps adding oxygen reduced the stickiness by changing the molecules’ shape.

He presented his ideas as a research problem to Harvey Itano, a young physician who was then working on his Ph.D. in Pauling’s laboratory. Itano, later joined by postdoctoral fellow John Singer, worked for a year trying to see if sickle-cell hemoglobin was shaped differently from normal hemoglobin. They found no detectable differences in any of the tests they devised. But they kept at it. Finally, in 1949, using an exquisitely sensitive new technique called electrophoresis that separated molecules by their electric charge, they found their answer: Sickle-cell hemoglobin carried more positive charges on its surface.

This was an astounding discovery. A slight change in the electrical charge of a single type of molecule in the body could spell the difference between life and death. Never before had the cause of a disease been traced to a molecule. This discovery – to which Pauling attached the memorable title “molecular disease” – received widespread attention. Itano and Singer’s followup work demonstrated the pattern of inheritance for the disease, firmly wedding molecular medicine to genetics.

Medical Chemistry

It was a great triumph – there was talk of a Nobel Prize in Medicine or Physiology for Pauling – and it led Pauling to make greater efforts in the medical field. He encouraged M.D./Ph.D. candidates, hired physicians to work in his laboratory, and began focusing his own research on medical problems, including developing a new theory of anesthesia.

He was ahead of his time. An example of what the atmosphere was like: Pauling noted that as he went around in the late 1940s seeking funds for a comprehensive marriage of biology and chemistry to attack medical problems, people at funding agencies were telling him that they found the term “medical chemistry” to be “a disturbing description.”

In the late 1950s, Pauling extended his concept of molecular disease to the brain. After reading about phenylketonuria (PKU) – a condition in which a mental defect can be caused by the body’s inability to metabolize an amino acid, phenylalanine, leading to a buildup of that substance and others in the blood and urine – Pauling theorized that the problem might be caused by a defect in an enzyme needed to break down phenylalanine. PKU, in other words, might be another molecular disease. Now interested in the possibility that there might exist a range of molecular mental defects, Pauling visited a local mental hospital, saw other patients whose diseases seemed hereditary, and decided to seek support for an investigation into the molecular basis of mental disease. The Ford Foundation in 1956 awarded him $450,000 for five years’ work – a vindication of Pauling’s approach and a tribute to his reputation. The grant, however, yielded little in the way of immediate results, with much of the funding going toward testing his (ultimately found to be mistaken) theory of anesthesia.

The long-term results were more significant. Pauling’s immersion in the field, thanks to the Ford grant, led him to read widely in psychiatry and general health, always on the lookout for another molecular disease that might lend itself to new therapy. By the mid-1960s he was coalescing his findings into another overarching theory, this one combining much of what he knew about chemistry and health. He called his new idea “orthomolecular” medicine.