Leonor Michaelis

Early life and education

Leonor Michaelis was born in Berlin, Germany, on 16 January 1875 to Jewish parents Hulda and Moritz https://www.geni.com/people/Leonor-Michaelis/6000000011560390598 . He had three brothers and one sister. Michaelis graduated from the humanistic Köllnisches Gymnasium in 1893 after passing the Abiturienten Examen. It was during that time that Michaelis's interest in physics and chemistry was first sparked as he was encouraged by his teachers to utilize the relatively unused laboratories at his school.

With concerns about the financial stability of a pure scientist, he commenced his study of medicine at Berlin University in 1893. Among his instructors were Emil du Bois-Reymond for physiology, Emil Fischer for chemistry, and Oscar Hertwig for histology and embryology.

During his time at Berlin University, Michaelis worked in the lab of Oscar Hertwig, even receiving a prize for a paper on the histology of milk secretion. Michaelis's doctoral thesis work on cleavage determination in frog eggs led him to write a textbook on embryology. Through his work at Hertwig's lab, Michaelis came to know Paul Ehrlich and his work on blood cytology; he worked as Ehrlich's private research assistant from 1898 to 1899.

He passed his physician's examination in 1896 in Freiburg, and then moved to Berlin, where he received his doctorate in 1897. After receiving his medical degree, Michaelis worked as a private research assistant to Moritz Litten (1899–1902) and for Ernst Viktor von Leyden (1902–1906).

Life and work

From 1900 to 1904, Michaelis continued his study of clinical medicine at a municipal hospital in Berlin, where he found time to establish a chemical laboratory. He attained the position of Privatdocent at the University of Berlin in 1903. In 1905 he accepted a position as director of the bacteriology lab in the Klinikum Am Urban, becoming Professor extraordinary at Berlin University in 1908. In 1914 he published a paper suggesting that Emil Abderhalden's pregnancy tests could not be reproduced,{{cite journal | trans-title = Abderhalden's pregnancy test

In 1926, he moved to Johns Hopkins University in Baltimore as resident lecturer in medical research and in 1929 to the Rockefeller Institute of Medical Research in New York City, where he retired in 1941.

The Michaelis–Menten equation

Michaelis's work with Menten led to the Michaelis–Menten equation.{{cite journal |trans-title = The kinetics of invertin action |translator-last = Boyde |translator-first = T.R.C |doi-access=free

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).

An equation of the same form and with the same meaning appeared in the doctoral thesis of Victor Henri, a decade before Michaelis and Menten.{{cite journal

Classification of Inhibition types

Michaelis was one of the first to study enzyme inhibition, and to classify inhibition types as competitive or non-competitive.{{cite journal with no effect on the apparent value of V/K_\mathrm{m}, was not considered by Michaelis. Fuller discussion can be found elsewhere.{{cite book

Hydrogen ion concentration

Michaelis built virtually immediately on Sørensen's 1909 introduction of the pH scale with a study of the effect of hydrogen ion concentration on invertase,{{cite journal

Quinones

In his later career he worked extensively on quinones, and discovered Janus green as a supravital stain for mitochondria and the Michaelis–Gutmann body in urinary tract infections (1902). He found that thioglycolic acid could dissolve keratin, a discovery that would come to have several implications in the cosmetic industry, including the permanent wave ("perm").

A full discussion of his life and contributions to biochemistry may be consulted for more information.

"Catalysing" the Suzuki method of music teaching

During his time in Japan Michaelis knew the young Shinichi Suzuki, later famous for the Suzuki method of teaching the violin and other instruments. Suzuki asked his advice about whether he should become a professional violinist. Perhaps more honest than tactful, Michaelis advised him to take up teaching, and thus catalysed the invention of the Suzuki method.{{cite journal | doi-access = free

Personal life and death

Michaelis was married to Hedwig Philipsthal; they had two daughters, Ilse Wolman and Eva M. Jacoby. Leonor Michaelis died on 8 October 1949 in New York City.

Honors

Michaelis was a Harvey Lecturer in 1924 and a Sigma Xi Lecturer in 1946. He was elected to be a Fellow of the American Association for the Advancement of Science in 1929, a member of the National Academy of Sciences in 1943. In 1945, he received an honorary LL.D. from the University of California, Los Angeles.

References

References

1. [http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/michaelis-leonor.pdf Leonor Michaelis 1875–1949] A Biographical Memoir by L. Michaelis, D. A. MacInnes and S. Granick J
2. (June 2016). "Leonor Michaelis and Maud Leonora Menten".
3. (2006). "Leonor Michaelis in Japan". IUBMB Life.
4. Nagatsu, T.. (2013). "In memory of Professor Leonor Michaelis in Nagoya: Great contributions to biochemistry in Japan in the first half of the 20th century". FEBS Lett..
5. V. Henri: Théorie générale de l’action de quelques diastases. ''C. R. Hebd. Séances Acad. Sci.'' 135 (1902) 916–919
6. (2013). "Commemorating the 1913 Michaelis–Menten paper ''Die Kinetik der Invertinwirkung'': three perspectives". FEBS J..
7. or 10 October,[http://www.whonamedit.com/doctor.cfm/2090.html Whonamedit Biography]