2 Mildred Cohn

Mildred Cohn was a pioneer in the scientific community during a time when hardships and adversities were common obstacles facing women. Born in 1913, Cohn grew up in New York City to a Jewish family and showed outstanding academic achievement at a young age. However, the rest of society viewed her as inferior for her gender and religion. Since she was a woman, professors discouraged her from becoming a chemist while teaching her to become a chemistry teacher, saying that a career as a chemist was “unladylike.” Further, she was denied many opportunities for her Jewish religion, as only Christians were allowed in most science-based positions. Nonetheless, Cohn defied the odds and made her career working alongside Nobel Peace Prize winners, earning a Professional Doctorate in Physical Chemistry, and discovering connections between biology and chemistry. Ultimately, Cohn pushed past adversity and became a successful and educated chemist in an era where most women were housewives and Jewish people were viewed as inferior.

Growing up, Cohn was raised by her father alongside her brother Albert, who was two years older than her. Her father was a rabbi in Russia before moving to New York in 1907, leading to their family to place major emphasis on Yiddish culture. When Cohn was 13, her family moved to a Yiddish-speaking cooperative. This proved very beneficial to Cohn as the cooperative emphasized educational attainment, which would help Cohn later in life.

Cohn started her college education at Hunter University in New York City, a university that was free and accepting of women. However, Cohn eventually saved up enough money to attend the University of Columbia and receive her Masters’ degree. In 1938, Cohn married Henry Primakoff but chose not to change her last name because she didn’t want her Jewish identity revealed during World War II. In 1960, Cohn and her husband moved to the University of Pennsylvania, where they would work for the rest of their careers. However, Cohn’s husband would pass away at 69.

Much like her personal life, Cohn’s professional life was greatly impacted by discrimination for her gender and religion. Despite the trials of her personal life, Mildred Cohn continued to advance her research despite the gender bias and prejudice she faced. Cohn refused the recommendation from her peers to stop after her bachelor’s degree, and in 1932, just a year after completing her bachelor’s, she earned her master’s degree in Chemistry from the University of Columbia. However, Cohn could not attend an extra year of her graduate program, as the Great Depression led to a national economic crisis. Individuals all over the United States could not afford basic needs such as food, clothes, or shelter. While Cohn was able to afford for her basic needs, she was unable to afford school. Reflective of the discrimination she faced, there were programs such as teaching assistantships to help, but since Cohn was not Christian or male, she was not allowed to participate in these financial opportunities.

Rather than taking an assistantship, Cohn had to find another way to pay for her education. She took a job at a government aeronautics lab to save up money, a process that took two years. This lab was the predecessor to The National Aeronautics and Space Administration or NASA. Eventually, the director heard there was a female in his lab who was doing more advanced experiments than her male counterparts, and Cohn was kicked out of the lab solely because she was female. After a lot of convincing, she worked under Nobel Peace Prize winner Harold Urey where she wrote her Ph.D. dissertation over the behavior of isotopes of oxygen. This work allowed her to achieve her doctorate in Physical Chemistry from Colombia in 1938 and laid the foundations for her career as a chemist.

Cohn’s work both at the government aeronautics lab and at Colombia focused primarily on using mass spectrometry (MS). This technique would bombard samples with high energy until they broke apart, and then measure the ratio of mass-to-charge of the fragments of the molecule. This allows for identification of the compound placed inside the instrument. Mass spectrometers are very expensive and complicated instruments, however, at both of these institutions, Cohn built her own mass spectrometers. She was not only able to build these incredibly complicated instruments, but was also an expert in their usage.

Cohn was now an established figure in chemical science. However, this did not mean that her male counterparts respected her. Cohn eventually ended up at Washington University as a post-doctorate researcher. Her position there was largely because her husband was offered a position there as well, but Cohn was able to take full advantage of this opportunity. She began to work with Gerty Cori, another chemist discussed in this book, and at this time she started her work studying adenosine triphosphate (ATP) with nuclear magnetic resonance (NMR).

NMR is a complicated process that helps determine the identity and structure of compounds. The NMR creates a strong magnetic field, and nuclei that contain an odd mass number interact with the magnetic field producing a signal. These signals can be converted to peaks which differ based on the polarity of nearby atoms. The more polar the area around the atom is, the more the peak moves to the left of the spectrum. These are called ‘down-field’ peaks.

Cohn used NMR to study ATP, the primary source of energy that our body uses. She looked for 31P, which contains the odd mass number necessary for NMR, and through her work she was able to define each phosphate group present on ATP. Using this method she was also able to study how ATP was converted to ADP which produces energy, and how ADP was converted back into ATP to store energy. This process of creating energy, called the metabolic pathway, had been proposed before, but Cohn’s work was the first time that direct evidence for it had been seen.

Perhaps more importantly, NMR, the process Cohn was using, was non-destructive. Her previous work with MS would completely destroy the valuable samples they were attempting to analyze, but NMR used weaker fields, and thus the sample was not destroyed in the process of measuring it. This allowed for Cohn to study what happens to samples over time, which eventually became her work studying the metabolic pathway.

Cohn worked with Cori for 22 years before eventually being offered a professorship at the University of Pennsylvania in 1960, where she continued to work for another 22 years before she retired. Cohn was a remarkable chemist as she not only build her own instruments and became an expert in mass spectrometry, but was able to change and also become one of the most prolific chemists working with NMR. Over the course of her career Cohn published over 160 papers, many of them concerning the metabolic pathways that occur in humans. This work not only increased our knowledge of how energy is produced in us, but also helped with the identification and diagnosis of several diseases.