Cohn, Edwin Joseph
Cohn, Edwin Joseph
(b. New York, N. Y., 17 Decmber 1892; d. Boston, Massachusetts, 1 October 1953),
Cohn was a notable leader in the study of proteins. After taking his Ph.D. (1917) with L. J. Henderson of Harvard and F. R. Lillie of the University of Chicago, he worked with T. B. Osborne in New Haven and S. P. L. Sørensen in Copenhagen. Returning to Harvard Medical School in 1920, he joined the new department of physical chemistry, then headed by Henderson (and later by Cohn himself). He initiated active research on the solubilities in different media and their acidic and basic properties. From 1926 to 1932 he also studied the factor in liver that G. R. Minot had shown to be effective against pernicious anemia. Cohn obtained a highly active preparation of great clinical use but failed to isolate the pure active principle (vitamin B-12), which was obtained by others in 1948.
About 1930 Cohn turned his attention to the amino acids and peptides, the smaller building blocks of which proteins are composed. These are extraordinarily polar molecules, containing widely separated centers of positive and negative charge. They also contain various polar and nonpolar side chains. Over a period of ten years Cohn and his associates, G. Scatchard, J. G. Kirkwood, T. L. McMeekin, J. P. Greenstein, J. Wyman, J. T. Edsall, J. L. Oncley, and others, established many systematic relations between the structures of these molecules and their physical properties—dipole moments, solubilities, apparent molal volumes, ionization constants, and infrared and Raman spectra. They showed how to describe influences of electric charge and dipole moment, and of various polar and nonpolar side chains, in quantitative terms, thus laying a foundation for the further study of proteins.
This work provided the background essential for the next major phase of Cohn’s activities, which coincided with the outbreak of World War II. Supported by the Office of Scientific Research and Development, he initiated and directed a major program, involving biochemists, clinicians, and many others, for the large-scale fractionation of human blood plasma. This yielded purified serum albumin for treatment of shock, gamma globulin for passive immunization against measles and hepatitis, fibrinogen and fibrin for neurosurgery, and numerous other protein fractions of blood plasma. The methods developed in the laboratory and its pilot plant were rapidly applied on an industrial scale, and the products were distributed for large-scale use by the armed forces and later in civilian medicine. Apart from its practical results, this program led to a great advance in knowledge of the chemistry and physiology of the multifarious components of blood plasma.
After the war the fame of this work attracted young investigators from all over the world to Cohn’s laboratory, and he continued to contribute actively to the advancement of protein chemistry until his death.
I. Original Works. Chon’s writings include “The Physical Chemistry of Proteins,” in Physiological Reviews, 5 (1925), 349–437; “Die physikalische Chemie der Eiweisskörper,” in Ergebnisse der Physiologie (biologischen Chemie and experimentellen Pharmakologie), 33 (1931), 781–882; “The Chemistry of the Proteins and Amino Acids,” in Annual Review of Biochemistry, 4 (1935), 93–148; Proteins, Amino Acids and Peptides as Ions and Dipolar Ions, American Chemical Society Monograph no. 90 (New York, 1943), written with J. T. Edsall; and “The History of Plasma Fractionation,” in Advances in Military Medicine, I (Boston, 1948), 364–443. Cohn published numerous papers in the Journal of Biological Chemistry, the Journal of the American Chemical Society, and elsewhere, between 1920 and 1953.
II. Secondary Literature. There are two biographical articles on Cohn by J. T. Edsall: in Ergebnisse der Physiologie (biologischen Chemie and experimentellen Pharmakologie), 48 (1955), 23–48; and in Biographical Memoirs. National Academy of Sciences, 35 (New York, 1961), 47–84. Both contain essentially complete bibliographies of Cohn’s publications. The former also lists a number of publications from his laboratory to which his name was not attached; the latter article provides more extensive details about his life and work.
John T. Edsall
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