Vision of LIFE - Jaargang 16 - Nr. 1

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17
History of LST (2): Albrecht Kossel
Wetenschap
In the first edition of ‘The history of DNA’ you read about the Swiss Friedrich Miescher,
the first person to isolate DNA. Friedrich identified the substance and called it ‘nuclein’,
since the only thing he knew for sure, was that the substance could be found in the
nucleotide of a cell. He had already suggested that nuclein played an important role
in fertilization, but he could only speculate about the exact role and composition of
nuclein. It was Albrecht Kossel who identified the nucleic acids that are the components
of the substance that Miescher first isolated. In this second edition of ‘The history of
DNA’ the VoLcie will look into the life of this Albrecht Kossel.
Albrecht Kossel (Figure 1) was a German who
was born in Rostock in 1853. As a young man, he
was very interested in botany, but his father, a
merchant, pushed him to study medicine. He
started in 1872 at the University of Strassburg, a
University that had just been founded. In 1877,
he passed the medical examination. During
college, he was already inspired by the lectures
of Hoppe-Seyler, the man we all know from the
last edition of history of DNA; Friedrich Miescher
worked for him when he discovered ‘nuclein’.
Albrecht received his PhD in 1878 and he becames
the assistant of Hoppe-Seyler. In the next few
years, Kossel continued the research of Miescher,
and he found that the ‘nuclein’ partly consisted
of proteins, and partly of non-protein molecules:
nucleic acids.
“He showed that nucleic acids were
made up for a part out of purines or
pyrimidines”
Figure 2 Structure of cytosine, thymine, guanine, uracil,
adenine
Kossel discovered the four bases which make up
DNA; adenine, guanine, thymine and cytosine.
Later he also isolated uracil, the nucleic acid that
is present in RNA. He found several structural
parts of these building blocks of DNA and RNA,
he showed that nucleic acids were partly made
up of purines or pyrimidines and also showed the
structures of the both; pyrimidine has a single sixsided
ring and purine has a six-sided ring and a
five-sided ring who share one side with each other
(Figure 2).
“in recognition of the contributions
to our knowledge of cell chemistry
made through his work on proteins,
including the nucleic substances”
these four atoms, but adenine, the other purine,
did not contain any oxygen (Figure 2).
“The influence of Kossel became
larger and larger, ... he became the
director of the chemical division of the
institute of physiology in Berlin.”
The influence of Kossel became larger and
larger; in 1881 he qualified as lecturer and he
became the director of the chemical division of
the institute of physiology in Berlin. In 1887 he
became extraordinary professor in the medical
faculty of Freiburg and later in Marburg, where
he also became the director of the institute
of physiology. Some years later he moved to
Heidelberg and became the chairman of the
seventh international Congress of Physiology,
and for two years he was the pro-rector of the
University there. His influence was not only
present in Germany, Kossel was also honorary
doctor of the Universities of Cambridge, Dublin,
Ghent, St Andrews and Edinburgh and he was the
member of some academies as the Royal Swedish
Academy of Science and the Royal Society of
Uppsala.
During the nineties, he shifted the subject of his
investigations from the cell nucleus to proteins.
For instance, he studied the effects of a phenetole
diet on urine, peptonic components of the cell
and in 1896 he discovered an important protein
Figure 4 Nobel prize documentation
which we LST students all know: histone. Histones
are the proteins that help package DNA into the
structural units called nucleosomes (Figure 3).
In 1910 Albrecht Kossel’s work on the discovery of
the five nucleic acids was rewarded: he received
the Nobel prize in Physiology of Medicine “in
recognition of the contributions to our knowledge
of cell chemistry made through his work on
proteins, including the nucleic substances”
(Figure 4).
“He found that the ‘nuclein’ consisted
for a part out proteins, and for a part
out of a non-protein molecules”
Two years later Kossel gave a famous lecture in
which he explained the importance of nucleic
acids and the cellular proteins, which he
dsicovered, as the chemical basis for genetics, in
which he was completely right.
Kossel was married with Luise Holtzmann and
had a daughter and a son, Walther. Walther also
became famous as a scientist, as he discovered
X-ray interference in crystals. Albrecht Kossel
died on July 5, 1927 after a short sickbed.
Jolanda ter Horst
Wetenschap
Figure 1 Albrecht Kossel potret
Kossel discovered that the three pyrimidines,
thymine, cytosine and uracil consisted out of
carbon, hydrogen, nitrogen and oxygen. Guanine,
one of the two purines, also consisted out of
Figure 3 Nucleosomes