Editing Linus Pauling (section)

===Molecular genetics===
[[File:Linus Pauling 1948.png|thumb|Pauling in 1948]]

In November 1949, Pauling, [[Harvey Itano]], [[Seymour Jonathan Singer|S. J. Singer]] and Ibert Wells published "[[Sickle Cell Anemia, a Molecular Disease]]"<ref name="Itano">{{Cite journal |last1=Pauling |first1=L. |last2=Itano |first2=H. A. |last3=Singer |first3=S. J. |author3-link=Seymour Jonathan Singer |last4=Wells |first4=I. C. |date=November 25, 1949 |title=Sickle Cell Anemia, a Molecular Disease |url=http://scarc.library.oregonstate.edu/coll/pauling/blood/papers/1949p.15.htmlfddsf |journal=Science |volume=110 |issue=2865 |pages=543–548 |bibcode=1949Sci...110..543P |doi=10.1126/science.110.2865.543 |pmid=15395398 |s2cid=31674765 |access-date=June 2, 2015 }}{{Dead link|date=May 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> in the journal ''Science''. It was the first proof of a human disease being caused by an abnormal protein, and [[sickle cell anemia]] became the first disease understood at the molecular level. (It was not, however, the first demonstration that variant forms of hemoglobin could be distinguished by electrophoresis, which had been shown several years earlier by [[Maud Menten]] and collaborators).<ref>{{Cite journal |last1=Andersch |first1=MA |last2=Wilson |first2=DA |last3=Menten |first3=ML. |year=1944 |title=Sedimentation constants and electrophoretic mobilities of adult and fetal carbonylhemoglobin |journal=Journal of Biological Chemistry |volume=153 |pages=301–305 |doi=10.1016/S0021-9258(18)51237-0 |doi-access=free}}</ref> Using [[electrophoresis]], they demonstrated that individuals with [[sickle cell disease]] have a modified form of hemoglobin in their [[red blood cell]]s, and that individuals with [[sickle cell trait]] have both the normal and abnormal forms of hemoglobin. This was the first demonstration causally linking an abnormal protein to a disease, and also the first demonstration that [[Mendelian inheritance]] determines the specific physical properties of proteins, not simply their presence or absence – the dawn of [[molecular genetics]].<ref name="Strasser">{{Cite journal |last=Strasser |first=Bruno J. |date=August 30, 2002 |title=Linus Pauling's "molecular diseases": Between history and memory |url=http://biologie.unige.ch/assets/brunostrasser/Strasser_AJMG_2002.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://biologie.unige.ch/assets/brunostrasser/Strasser_AJMG_2002.pdf |archive-date=October 9, 2022 |url-status=live |journal=American Journal of Medical Genetics |volume=115 |issue=2 |pages=83–93 |citeseerx=10.1.1.613.5672 |doi=10.1002/ajmg.10542 |pmid=12400054 |access-date=May 27, 2015}}</ref>

His success with sickle cell anemia led Pauling to speculate that a number of other diseases, including mental illnesses such as [[schizophrenia]], might result from flawed genetics. As chairman of the Division of Chemistry and Chemical Engineering and director of the Gates and Crellin Chemical Laboratories, he encouraged the hiring of researchers with a chemical-biomedical approach to mental illness, a direction not always popular with established [[California Institute of Technology|Caltech]] chemists.<ref name="LATimes1994">{{Cite news |date=August 21, 1994 |title=A Flamboyant Scientist's Legacy : Scholar: Linus C. Pauling's supporters and detractors join in calling the two-time Nobel winner one of the most significant figures of this century |work=Los Angeles Times |url=https://www.latimes.com/archives/la-xpm-1994-08-21-mn-29601-story.html |access-date=June 1, 2015}}</ref>{{rp|2}}

In 1951, Pauling gave a lecture entitled "Molecular Medicine".<ref>{{Cite web |last=Pauling |first=Linus |date=October 1951 |title=Molecular Medicine |url=http://scarc.library.oregonstate.edu/coll/pauling/blood/pictures/1951s.17.html |access-date=August 5, 2007 |publisher=Ava Helen and Linus Pauling Papers}}</ref> In the late 1950s, he studied the role of enzymes in brain function, believing that mental illness may be partly caused by enzyme dysfunction.  In the 1960s, as part of his interest in the effects of nuclear weapons, he investigated the role of mutations in evolution, proposing with his student Emile Zuckerkandl, the molecular evolutionary clock, the idea that mutations in proteins and DNA accumulate at a constant rate over time .<ref name="Morgan">{{Cite journal |last=Morgan |first=Gregory J. |date=1998 |title=Emile Zuckerkandl, Linus Pauling, and the molecular evolutionary clock, 1959–1965 |url=https://www.jstor.org/stable/4331476|journal=Journal of the History of Biology |volume=31 |issue=2 |pages=155–78| doi=10.1023/A:1004394418084|jstor=4331476 |pmid=11620303 |s2cid=5660841 |access-date=June 11, 2023|url-access=subscription }}</ref>