Albrecht Kossel | Biography

Albrecht Kossel isolated several major structural parts of the nucleic acids and discovered histidine, an essential amino acid. He received the 1910 Nobel prize in physiology or medicine for his work with the nucleic acids and cellular proteins.

Kossel was born in Rostock, Germany, where his father was a merchant. Kossel's first scientific love was botany, but he was convinced by his father to study medicine and received his medical license in 1877. He next went to the University of Strasbourg (then part of Germany), where he became interested in physiological chemistry and worked with Ernst Hoppe-Seyler on the nucleic acids. After serving on university faculties in Berlin and Marburg, in 1901 he became head of the physiology department at the University of Heidelberg.

Between 1877 and 1881 he served as Ernst Hoppe-Selyer's assistant and began his studies of the nucleic acids, which had been discovered ten years earlier by one of Hoppe-Selyer's pupils, the Swiss biochemist Johann Miescher. Miescher had called his substance nuclein because it was found in a cell's nucleus, and it was thought to be a phosphorus-rich protein. Kossel showed that nuclein was actually composed of a protein portion and a non-protein portion, which was the nucleic acid.

Over the next 20 years, Kossel and his own research team made important discoveries about the structure of both the nucleic acids and cellular proteins. He showed that nucleic acid is made up in part of purines and pyrimidines. He identified their structures, showing that a pyrimidine has a single six-sided ring, while a purine has a six-sided ring that shares one side with a five-sided ring. He isolated the two purines, adenine and guanine, which are now known to exist in both ribonucleic acid ( RNA) and deoxyribonucleic acid ( DNA). He also isolated the three pyrimidines-- thymine and cytosine, found in DNA, and uracil, which RNA contains instead of thymine. Adenine is composed of carbon, hydrogen, and nitrogen; the others also contain oxygen. In addition, he identified carbohydrates in the nucleic acids and made preliminary predictions about the types of sugars involved. His work was continued by the American biochemist Phoebus Levene, who had once studied with him. In addition to these findings, Kossel was the first to isolate the protein histone--a component of chromatin, the structural material of the chromosomes that supports the DNA.

Kossel was always motivated to find the biological functions of the chemicals he studied and isolated. In a famous 1912 lecture, he expressed his conviction about the importance of nucleic acids and cellular proteins as the chemical basis for genetics. He published many papers detailing his work and held honorary doctorates at six universities. He was also a member of the Royal Swedish Academy of Sciences and the Royal Society of Sciences of Uppsala.