2007-9-14

Kossel,(Karl Martin Leonhard )Albrecht, German biochemist, was born on Sep. 16th, 1853 in Rostock of Mecklenburg and died on Jul. 5th, 1927 in Heidelberg. The original will of Kossel was to learn botany, but his father thought it was useless, that made him transfer to medicine. In Strasbourg University, being influenced by the pioneer of earlier stage biochemistry at that time Hoppe Seyler, Kossel worked as an assistant of Hoppe Seyler for 4 years from 1877 and thus his was brought up to be a biochemist. Later, he worked under Du Bois-Reymond. In 1879, he began to have researches on a substance called nucleoprotein. The substance was separated by a student of Hoppe Seyler, Michel ten years ago and Hoppe Seyler had researches on it himself. But it was an unidentified substance before it came to Kossel. The researches of Kossel started from pointing out that the nucleoprotein included protein parts and non-protein parts; therefore it could not be called by the unclear nucleoprotein, but called nucleic protein, in which the non-protein parts were "nucleic acid". This protein was very similar with other proteins, but the nucleic acid was different from the other known natural substances at that time. When the nucleic acid decomposed, Kossel discovered that there were nitrogenous compounds purine and pyrimidine in the resolvent of the nucleic acid, which atoms arranged into 2 ring and 1 ring respectively (Fisher once had researches on purine). Kossel separated two different purines: adenine and guanine and three different pyrimidines: thymine (separated firstly), cytosine and uracil. He also distinguished a carbohydrate beyond the resolvent, but this part could only be left to another generation Levine to prove. There were a large amount of nucleic acid in spermatozoon, and Kossel continued to research the proteins in spermatozoon cells. He discovered that there were abundant histidines-a kind of amino acid in cells. These proteins were rather simpler than the proteins in common cells. Kossel derived a quite elaborate structure theory of common proteins from the research on the solo nucleolus of spermatozoon. But from there he was in a dead end, because he did not discover (actually this was not discovered for nearly more than half a century) that the critical compound in spermatozoon and all cells was nucleic acid but not protein and the nucleic acid existed in spermatozoon cell in a very complex form. Even though Kossel was not conscious about the overall importance meanings of nucleic acid researches, his work left a profound impression to others. In 1895, he was appointed as professor of physiology in University of Marburg and in 1901, he replaced a famous professor to be as professor of physiology in University of Heidelberg. Kossel won the Nobel Prize in Physiology or Medicine 1910 for his researches on proteins and nucleic acid.