(b. Boczki, near Kielce. Russia [now Poland]. 15 January 1847; d. St. Petersburg, Russia, 14 December 1901)
Nencki was the son of Wilhelm Nencki, a landowner, and the former Katarzyna Serwaczyńska. In 1863 he graduated from a classical secondary school in Piotrków Trybunalski; active participation in the Polish uprising made his situation uncertain and forced him to emigrate. For about a year Nencki studied philosophy and ancient languages at the University of Berlin before transferring to the Medical Faculty of the same university, where he studied the chemistry of living organisms. To increase his knowledge of inorganic and organic chemistry, Nencki worked during two years of his medical studies under the direction of Baeyer in his laboratory at the Gewerbeinstitut.
While still a university student Nencki published, with his friend O. Schultzen, a paper dealing with precursors of urea in mammals. He received the M.D. in 1870 with a dissertation on the oxidation of aromatic compounds in the body. In 1871 Nencki published a paper related to the chemistry of uric acid and similar compounds. These three subjects were the center of his interest throughout his life.
Nencki’s initial publications appeared to be of such value that shortly after receiving the M.D. he was engaged as an assistant at the University of Bern, where his scientific career developed swiftly. Within a few years he was appointed to a professorship and became head of the department of biochemistry. A pioneer of a chemical approach to microorganisms, he also lectured on pharmacology and bacteriology. Nencki became an internationally recognized authority on biochemistry and theoretical medicine, attracting students from all parts of Europe and America.
In 1890 Nencki left Switzerland for St. Petersburg, to help organize a new institute of experimental medicine. As head of the department of chemistry and biochemistry he began work in a new building specially constructed and equipped according to his plans. Partly in collaboration with Pavlov, who was head of the department of physiology, Nencki started to reinvestigate the method and site of formation of urea in the body. These fundamental and beautiful experiments showed that urea is formed chiefly, if not exclusively, in the liver. According to Nencki, urea was synthesized from amino groups of amino acids and from carbon dioxide and did not preexist in the protein molecule, as was then quite generally believed. This important idea anticipated modern views of the utilization of carbon dioxide in certain synthetic processes that occur in the animal body. Speculating on the various possibilities of biosynthesis, especially of fatty acids, Nencki proposed a hypothesis according to which a gradual condensation of some active two-carbon-atom fragments takes place; a splitting-off of these fragments may occur during oxidation. This hypothesis, together with the results of Nencki’s earlier investigation on the oxidation of aromatic compounds in the animal body, formed a basis for Knoop’s β oxidation theory. Nencki supposed that the active two-carbon-unit compound was acetaldehyde and hence, in principle, he was not far from the modern view of the role of acetyl coenzyme A.
Nencki’s best-known investigations concerned hemoglobin. Using original methods he systematically studied for many years the degradation products of this blood pigment. Somewhat later Marchlewski, working first in England and later in Cracow, performed similar studies on chlorophyll. It soon appeared that some of the degradation products of these two pigments resembled each other. Nencki and Marchlewski thus initiated a peculiar art of collaboration at a distance. They exchanged and carefully investigated the particular degradation products of the pigments and finally obtained, both from hemoglobin and from chlorophyll, the same substance, hemopyrrole.
On the basis of these results Nencki put forward a hypothesis concerning the chemical relationship between the animal and plant kingdoms. He planned vast investigations in the field, which now would be called evolutionary biochemistry. Unfortunately these plans were not realized; at the end of 1901 Nencki died of stomach cancer.
Nencki’s work is unusually impressive for its magnitude, as well as for the variety of the problems he investigated, the ingenuity and the precision of his experiments, and his perseverance in achieving his aims. His chief interest was biochemistry; but some of his papers deal with analytical and organic chemistry, bacteriology, pharmacology, pharmacy, hygiene, and practical medicine.
All of Nencki’s scientific life took place outside Poland, but he was always in contact with his motherland: he published many of his papers in Polish scientific journals, held an honarary doctorate from the University of Cracow, was a member of several Polish scientific societies, and often participated in Polish congresses. In accordance with his wishes, he was buried in Warsaw.
Shortly after Nencki’s death it was suggested that a scientific institute be built and named for him. This idea was not realized until 1918, with the creation of the Nencki Intstiute of Experimental Biology, devoted chiefly to biochemistry and physiology, in Warsaw.
Marceli Nencki. Opera omnia. Gesammelte Arbeiten von Prof. M. Nencki, Nadine Sieber and J. Zaleski, eds., (Brunswick, 1904), contains Nenck’s 150 papers and 450 papers by his colleagues at Bern and St. Petersburg.
Fifty Years of Activity of the M. Nencki Institute of Experimental Biology (1918–1968) (Warsaw, 1968), in Polish with English summaries, contains articles on the history of the Nencki Institute (W. Niemierko), the investigaiions of the physiology of the brain (J. Konorski), biochemistry (W. Niemierko), neurochemistry (Stella Niemierko), biology (S. Dryl), hydrobiology (R. Klekowski), data concerning the library of the Institute (H. Adler), and a complete list of workers there (1918–1968). Marceli Nencki, Materialy biograficzne i bibliograficzne, Aniela Szwejcerowa and Jadwiga Groszyńska, eds. (Warsaw, 1956), contains a full bibliography of Nencki’s works and of works on him, his correspondence with Marchlewski, some of his letters to his family, a biographical article by W. Niemierko, some other biographical articles, photographs, and documents. See also M. H. Bickel, Marceli Nencki 1847–1901 (Bern-Stuttgart-Vienna, 1972).