CHEM-342 INTRODUCTION TO BIOCHEMISTRY
Background for the article by Zinoffsky (1886)
Ueber die Grösse des Hämoglobinmolecüls
Hoppe-Seyler's Zeitschrift für Physiologische Chemie 10, 16 - 34
David Keilin (1887 - 1963), a renown physiologist-parasitologist at the University of Cambridge and a person who used a spectroscope to study heme proteins involved in cellular respiration, summarized clearly the significance of the discoveries of G.G.Stokes in our first article as follows:
"George G. Stokes entered the field of blood pigments through his interest in optics and spectroscopy. Although Hoppe-Seyler (1862) was first to describe the absorption spectrum of the red blood pigment (later named oxyhaemoglobin) with its two characteristic absorption bands, he failed to make proper use of his discovery. It was Stokes (1864) who discovered that when a red solution of blood is treated with a reducing agent (alkaline ferrous tartrate - known as Stokes' Solution) it becomes purplish and its two strong absorption bands are replaced by a single and more diffuse band. He observed that when this reduced solution is shaken with air, the colour and the absorption spectrum return to their original states. He identified the red and purple forms of the blood pigment with its state in arterial and venous blood, which he called scarlet cruorine and purple cruorine respectively. With this important discovery he established the function of the blood pigment and thus laid the foundation for physiological and biochemical studies of this pigment which, in its two states, was named oxyhaemoglobin and haemoglobin respectively by Hoppe-Seyler (1864). Having found an easy method by which to liberate haematin from haemoglobin, Stokes (1864) reduced the haematin in the presence of ammonia and obtained a pigment with two very strong absorption bands of 'reduced haematin.' "(1)
Stokes' article, though significant, represented his only publication on hemoglobin. At that time Germany was the center of the chemical world. Hünefeld had observed hemoglobin crystals in almost dry blood in 1840 and in 1851 Otto Funke describe how to crystallize hemoglobin (2). Chemists like to work with pure substances. Crystallization often indicates that a pure substance has been obtained. Hemoglobin, however, was not the typical organic molecule or inorganic salt that crystallizes. Its size dwarfed anything previously known or suspected. It attracted attention. In 1871 Wilhelm Preyer published Die Blutkrystalle, a book which illustrated crystalline hemoglobins from more than 40 species. Interesting and perhaps puzzling to 19th century chemists was the observation that the crystal form showed species specific characteristics (2). This normally implies different chemical compounds.
Among the scientists attracted to hemoglobin study was Felix Hoppe-Seyler (1825 -1895). In addition to being the first to observe the absorption spectrum of hemoglobin (3) and give the name hemoglobin, he also crystallized hemoglobin (4) and confirmed it contained iron. After crystallizing hemoglobin Hoppe-Seyler, who had been trained as a physiologist, shifted his interest to chemistry (5). He established the first laboratory devoted to what we would call biochemistry. Our next article, published in Hoppe-Seyler's journal by Zinoffsky, uses quantitative analytical methods to estimate the imperical formula (and by inference the size) of hemoglobin.
The fact that Zinoffsky wrote his article in German posed a considerable challenge to students in CHEM 342 in 1993 and highlighted how few biochemistry majors study the language. Several decades ago German was required for graduation in chemistry and biochemistry because so many important discoveries were published in German. Fortunately a translation of Zinoffsky's article by Cathy Saltern (BS 1993 in chemical education and German) eliminates translation as a learning issue this year. Given that English is the almost universal language of science, consider the communication problem of scientists for whom English is a foreign language.
1 Keilin, D. (1966) The History of Cell Respiration and Cytochrome, Cambridge University Press
2 Fruton, J. (1972) Molecules and Life - Historical Essays on the Interplay of Chemistry and Biology, Wiley-Interscience, New York
3 Hoppe, F. (1862) Ueber das Verhalten des Blutfarbstoffes im Spectrum des Sonnenlichtes. Virchows Arch. 23, 446 - 449
4 Hoppe-Seyler, F (1864) Ueber die chemischen und optischen Eigenschaften des Blutfarbstoffs. Virchows Arch 29, 233 - 235
5 Asimov, I. (1972) Asimov's Biographical Encyclopedia of Science and Technology, Doubleday & Co., Garden City, New York
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Last updated: 9 February 1999 by Hal White
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