Edwin Joseph Cohn
Encyclopedia
Edwin Joseph Cohn was an early protein scientist. A graduate of Phillips Academy, Andover [1911], and the University of Chicago [1914, PhD 1917], he made important advances in the physical chemistry
of protein
s, and was responsible for the blood fractionation
project that saved thousands of lives in World War II.
. Cohn's contribution allowed practical treatment of this previously incurable and fatal illness, for the next 20 years.
during World War II
.
In particular, he worked out the techniques for isolating the serum albumin
fraction of blood plasma
, which is essential for maintaining the osmotic pressure
in the blood vessel
s, preventing their collapse. Transfusion
s with purified albumin on the battlefield rescued thousands of soldiers from shock.
After the war
, Cohn worked to develop systems by which every component of donated
blood
would be used, so that nothing would be wasted.
On Cohn's office blackboard was inscribed a quotation from Goethe's Faust
: "Das Blut ist ein ganz besonderer Saft." (Blood is a very special juice.)
where
is the protein solubility constant and 
and 
are constants characteristic of the particular ion
S whose concentration (or, more correctly, activity
) is [S]. This equation is identical to the Setschenow solubility equation (Setschenow, 1889)
Cohn was a long-time collaborator and friend of another important physical chemist, George Scatchard.
published Proteins, Amino Acids and Peptides, a book that summarized the known physical chemistry of proteins and deeply influenced succeeding generations of protein scientists.
Cohn was also selfless in the best (and worst) scientific tradition. For example, he would often give public demonstrations of the blood fractionation machine, in which he would fractionate his own blood on the stage during the lecture. In one such lecture, at the Instituto Superior Técnico
in Lisbon
, the machine became blocked (without Cohn's knowledge) and exploded, showering the first few rows of the audience with Cohn's blood. Cohn maintained his sangfroid, however, and continued his lecture without significant interruption. More generally, Cohn drove himself relentlessly and ignored his doctors' advice to cut back on working because of his high blood pressure (which finally killed him).
However, Cohn was also well-known for being harsh and demanding of his subordinates, being something of a martinet
.
Cohn died on 1 October 1953 in Boston, of a stroke brought on by hypertension
caused by an undiagnosed pheochromocytoma
.
Physical chemistry
Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts...
of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s, and was responsible for the blood fractionation
Blood fractionation
Blood fractionation is the process of fractionating whole blood, or separating it into its component parts. This is typically done by centrifuging the blood.The resulting components are:...
project that saved thousands of lives in World War II.
Liver juice fractionation and concentration for treatment of pernicious anemia
In 1928, while at Harvard, Cohn was able to concentrate, by a factor of 50 to 100 times, the vital factor in raw liver juice which had been shown by Minot and Murphy to be the only known specific treatment for pernicious anemiaPernicious anemia
Pernicious anemia is one of many types of the larger family of megaloblastic anemias...
. Cohn's contribution allowed practical treatment of this previously incurable and fatal illness, for the next 20 years.
Blood fractionation project
Cohn became famous for his work on blood fractionationBlood fractionation
Blood fractionation is the process of fractionating whole blood, or separating it into its component parts. This is typically done by centrifuging the blood.The resulting components are:...
during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
In particular, he worked out the techniques for isolating the serum albumin
Serum albumin
Serum albumin, often referred to simply as albumin is a protein that in humans is encoded by the ALB gene.Serum albumin is the most abundant plasma protein in mammals. Albumin is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular...
fraction of blood plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
, which is essential for maintaining the osmotic pressure
Oncotic pressure
Oncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins in blood plasma that usually tends to pull water into the circulatory system.Throughout the body, dissolved compounds have an osmotic pressure...
in the blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s, preventing their collapse. Transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
s with purified albumin on the battlefield rescued thousands of soldiers from shock.
After the war
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, Cohn worked to develop systems by which every component of donated
Blood donation
A blood donation occurs when a person voluntarily has blood drawn and used for transfusions or made into medications by a process called fractionation....
blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
would be used, so that nothing would be wasted.
On Cohn's office blackboard was inscribed a quotation from Goethe's Faust
Faust
Faust is the protagonist of a classic German legend; a highly successful scholar, but also dissatisfied with his life, and so makes a deal with the devil, exchanging his soul for unlimited knowledge and worldly pleasures. Faust's tale is the basis for many literary, artistic, cinematic, and musical...
: "Das Blut ist ein ganz besonderer Saft." (Blood is a very special juice.)
Physical chemistry of proteins
Cohn is also well-remembered for his studies of the physical chemistry of proteins, particularly his general "salting out" equation for protein solubility (1925)where
is the protein solubility constant and and are constants characteristic of the particular ionIon
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
S whose concentration (or, more correctly, activity
Activity (chemistry)
In chemical thermodynamics, activity is a measure of the “effective concentration” of a species in a mixture, meaning that the species' chemical potential depends on the activity of a real solution in the same way that it would depend on concentration for an ideal solution.By convention, activity...
) is [S]. This equation is identical to the Setschenow solubility equation (Setschenow, 1889)
Cohn was a long-time collaborator and friend of another important physical chemist, George Scatchard.
A most important book
In 1943, Cohn and John EdsallJohn Tileston Edsall
John Tileston Edsall was anearly protein scientist, who contributed significantly to theunderstanding of the hydrophobic interaction.-Protein research:In 1943, Edsall and Cohn published a...
published Proteins, Amino Acids and Peptides, a book that summarized the known physical chemistry of proteins and deeply influenced succeeding generations of protein scientists.
Personality
Cohn was an excellent project leader, being driven, ambitious, and extremely well organized. He also had a keen taste in people and scientific projects and could sense when either would be successful. The success of the blood fractionation project was due in great part to his management, and he can be considered responsible for saving thousands of lives.Cohn was also selfless in the best (and worst) scientific tradition. For example, he would often give public demonstrations of the blood fractionation machine, in which he would fractionate his own blood on the stage during the lecture. In one such lecture, at the Instituto Superior Técnico
Instituto Superior Técnico
Instituto Superior Técnico is a reputed school of engineering, part of Universidade Técnica de Lisboa . IST is the largest and the most prestigious school of engineering in Portugal...
in Lisbon
Lisbon
Lisbon is the capital city and largest city of Portugal with a population of 545,245 within its administrative limits on a land area of . The urban area of Lisbon extends beyond the administrative city limits with a population of 3 million on an area of , making it the 9th most populous urban...
, the machine became blocked (without Cohn's knowledge) and exploded, showering the first few rows of the audience with Cohn's blood. Cohn maintained his sangfroid, however, and continued his lecture without significant interruption. More generally, Cohn drove himself relentlessly and ignored his doctors' advice to cut back on working because of his high blood pressure (which finally killed him).
However, Cohn was also well-known for being harsh and demanding of his subordinates, being something of a martinet
Martinet
The martinet is a punitive device traditionally used in France and other parts of Europe. The word also has other usages . It is also a term for a type of hammer in French, a diminutive of marteau , "hammer".-Object:...
.
Historical dates
Edwin J. Cohn was born on 17 December 1892 in New York City to Abraham and Maimie Einstein Cohn.Cohn died on 1 October 1953 in Boston, of a stroke brought on by hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
caused by an undiagnosed pheochromocytoma
Pheochromocytoma
A pheochromocytoma or phaeochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands , or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually noradrenaline , and adrenaline to a lesser extent...
.
External links
- PBS biography written by John Tileston EdsallJohn Tileston EdsallJohn Tileston Edsall was anearly protein scientist, who contributed significantly to theunderstanding of the hydrophobic interaction.-Protein research:In 1943, Edsall and Cohn published a...