Leonor Michaelis

Leonor Michaelis ( born January 16, 1875 in Berlin, † October 8, 1949 in New York City ) was a German - American biochemist and physician.

Life

Leonor Michaelis was born in 1875 in Berlin as the son of the merchant Moritz Michaelis. He graduated from the Gymnasium in Berlin Köllnische. By 1915 he was a member of the Orthodox Jewish community Adass Yisroel. Michaelis studied medicine from 1893 at the Universities of Freiburg and Berlin, where he received his doctorate in 1897. Among his academic teachers were Emil Fischer in chemistry, Oscar Hertwig in embryology and Emil du Bois- Reymond in physiology. After graduation, he was an assistant with Paul Ehrlich ( 1898-1899 ), Moritz Litten ( 1899-1902 ) and Ernst Victor von Leyden ( 1902-1906 ). From 1906 he headed the bacteriological laboratory at the Municipal Urban Hospital in Berlin, in 1908 he was appointed associate professor at the University of Berlin.

In 1922 he followed a call to the " Aichi Prefectural Medical College ", which later became the Medical Department of the University of Nagoya, was a professor of biochemistry. In 1926 he went to Johns Hopkins University in Baltimore, and finally in 1929 to the Rockefeller Institute for Medical Research in New York City.

Work

He was known primarily for his fundamental studies of the kinetics of enzymatic reactions, developed jointly with Maud Menten in 1910 Michaelis-Menten theory and introduced there Michaelis constant. The work was based on studies by the French chemist Henri Victor. He also did pioneering work in the study of the influence of pH, ie the hydrogen ion concentration or activity, on the activity of enzymes.

Even in his work with Paul Ehrlich began Michaelis, to deal with histological stains. He developed suitable methods for mitochondrial staining with the dye Janus Green B. He examined the eponymous Michaelis- Gutman bodies in urinary tract infections.

In 1914 he published an article in which he the theory of so-called " defensive ferments " by Emil Abderhalden rightly criticized by which a pregnancy test would supposedly possible. This bold public criticism of the time very established Abderhalden has unfortunately more difficult for him to get a full professorship in Germany.

Finally, he also recognized as a fundamental principle of permanent waves, the solubility of keratin in thioglycolic acid.

Writings (selection )

  • Introduction to dye chemistry. Berlin 1902.
  • Dynamics of the surfaces. Dresden 1909.
  • Introduction to Mathematics for biologists and chemists. Berlin 1912; 3rd edition, 1927.
  • The hydrogen ion concentration. Berlin 1914
  • Placement of physical chemistry. Berlin 1921
  • The effects of ions in colloidal systems. Berlin 1925.
  • The theoretical basis for the importance of the hydrogen concentration of the blood. In: Handbook of normal and pathological physiology. Band 6.1, Berlin 1928.
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