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Maud Leonora Menten
Maud Leonora Menten (1879-1960).jpg
Born (1879-03-20)20 March 1879
Port Lambton, Ontario
Died July 17, 1960(1960-07-17) (aged 81)
Leamington, Ontario, Canada
Nationality Canadian
Alma mater University of Toronto
Known for Michaelis-Menten equation, contributions to enzyme kinetics and histochemistry
Scientific career
Institutions
Thesis The Alkalinity of the Blood in Malignancy and Other Pathological Conditions; Together with Observations on the Relation of the Alkalinity of the Blood to Barometric Pressure (1916)

Maud Leonora Menten (March 20, 1879 – July 17, 1960) was a Canadian bio-medical and medical researcher who made significant contributions to enzyme kinetics and histochemistry. She is primarily known for her work with Leonor Michaelis on enzyme kinetics in 1913. The paper has been translated into English.

Maud Menten was born in Port Lambton, Ontario and studied medicine at the University of Toronto (B.A. 1904, M.B. 1907, M.D. 1911, Ph.D., 1916). She was among the first women in Canada to earn a medical doctorate. She completed her thesis work at University of Chicago. At that time women were not allowed to do research in Canada, so she decided to do research in other countries such as the United States and Germany.

In 1912 she moved to Berlin where she worked with Leonor Michaelis and co-authored their paper in Biochemische Zeitschrift which showed that the rate of an enzyme-catalyzed reaction is proportional to the amount of the enzyme-substrate complex. This relationship between reaction rate and enzyme–substrate concentration is known as the Michaelis–Menten equation.

After studying with Michaelis in Germany she entered graduate school at the University of Chicago where she obtained her PhD in 1916. Her dissertation was titled "The Alkalinity of the Blood in Malignancy and Other Pathological Conditions; Together with Observations on the Relation of the Alkalinity of the Blood to Barometric Pressure". Menten worked at the University of Pittsburgh (1923–1950), becoming Assistant Professor and then Associate Professor in the School of Medicine and head of pathology at the Children's Hospital of Pittsburgh. Her final promotion to full Professor, in 1948, was at the age of 69 in the last year of her career. Her final academic post was as a research fellow at the British Columbia Medical Research Institute.

Early life and work

The Menten family moved to Harrison Mills, British Columbia, where Maud's mother worked as a postmistress. After completing secondary school, Menten attended the University of Toronto where she earned a bachelor of arts degree in 1904 and a master's degree in physiology in 1907. While earning her graduate degree, she worked as a demonstrator in the university's physiology lab.

As Menten wanted to further her medical research, she found that opportunities in Canada were scarce for women at the time. As a result she accepted a fellowship at the Rockefeller Institute for Medical Research and left for in New York City in 1907; there she studied the effect of radium bromide on cancerous tumors in rats. Menten and two other scientists published the results of their experiment, producing the Rockefeller Institute's first monograph. Menten worked as an intern at the New York Infirmary for Women and Children. After a year at the Institute, Menten returned to Canada and began her studies at the University of Toronto where in 1911 she became one of the first Canadian women to qualify as a medical doctor.

The Michaelis-Menten Equation

In 1912, Menten came back to medical research, working with renowned surgeon George Crile, in whose honour the Crile crater on the Moon is named, on the control of acid-base balance during anaesthesia. Around this time she became acquainted with Leonor Michaelis, who was known then as one of the world-leading experts in pH and buffers. Menten became attracted to Michaelis' early work in enzyme kinetics, despite his modest laboratory establishment in Berlin, and made the difficult decision to cross the sea to work with Michaelis.

Michaelis and Menten expressed the relationship they were investigating as an equation:

v = \frac{Va}{K_\mathrm{m} + a}

for a steady-state rate v in terms of the substrate concentration a and constants V and K_\mathrm{m} (written with modern symbols). Victor Henri had included an equivalent equation in his thesis, but he did not use it and did not appreciate the importance of the steady state or the simplification that would result from considering the initial rate.

The equation shows not only that each enzyme is specific for its substrate, but also that the rate of reaction rate increases to saturation as the substrate concentration increases. The constant K_\mathrm{m} used in expressing this rate is now called the Michaelis constant. The paper deriving the Michaelis–Menten equation is Menten's most famous work.

Other work

After her research in Berlin, Menten enrolled in University of Chicago, where in 1916 she obtained a PhD in biochemistry. In 1923, she still could not find an academic position for women in Canada; she took a position as part of the faculty of the medical school at the University of Pittsburgh while serving as a clinical pathologist at Children’s Hospital in Pittsburgh. Despite the demands both jobs had, Menten found time to maintained an active research program, authoring or coauthoring more than 70 publications. Although her promotion from assistant to associate professor was timely, she was not made a full professor until she was 70 years old, within one year of retirement.

As part of extensive work on alkaline phosphatase, Menten invented the azo-dye coupling reaction, which is still used in histochemistry. This was described in a major textbook of the 1950s in the following terms:

It is not too much to say that the use of this principle was a stroke of genius.

She characterised bacterial toxins from B. paratyphosus, Streptococcus scarlatina and Salmonella ssp. that were used in a successful immunisation program against scarlet fever in Pittsburgh in the 1930s - 1940s. She also conducted the first electrophoretic separation of blood haemoglobin proteins in 1944. In this she anticipated the results of Linus Pauling and his collaborators by several years, but he is usually credited with the discovery. She worked on the properties of hemoglobin, regulation of blood sugar level, and kidney function.

She continued to work on cancer, especially in children, as well as other illnesses of children.

After her retirement from the University of Pittsburgh in 1950, she returned to Canada where she continued to do cancer research at the British Columbia Medical Research Institute (1951–1953).

Poor health forced Menten's retirement in 1955, and she died July 17, 1960, at the age of 81, in Leamington, Ontario.

Personal life

Rebecca Skloot portrays Menten as a petite dynamo of a woman who wore "Paris hats, blue dresses with stained-glass hues, and Buster Brown shoes." She drove a Model T Ford through the University of Pittsburgh area for some 32 years and enjoyed many adventurous and artistic hobbies. She played the clarinet, painted paintings worthy of art exhibitions, climbed mountains, went on an Arctic expedition, and enjoyed astronomy. By the time of her death, she mastered several languages, including Russian, French, German, Italian, and at least one Native-American language, Halkomelem. Although Menten did most of her research in the United States, she retained her Canadian citizenship throughout her life.

Honors

Throughout her career Menten was affiliated with many scientific societies.

At Menten's death, colleagues Aaron H. Stock and Anna-Mary Carpenter honored the Canadian biochemist in an obituary in Nature: "Menten was untiring in her efforts on behalf of sick children. She was an inspiring teacher who stimulated medical students, resident physicians and research associates to their best efforts. She will long be remembered by her associates for her keen mind, for a certain dignity of manner, for unobtrusive modesty, for her wit, and above all for her enthusiasm for research."

In 1998 she was posthumously inducted into the Canadian Medical Hall of Fame. She was also honored at the University of Toronto with a plaque and at the University of Pittsburgh with memorial lectures and a named chair. Port Lambton, Canada, where Menten was born, installed a commemorative bronze plaque about her in 2015.

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