Medicine and clinical chemistry Traube showed that sugar excretion in the urine of a diabetic patient rose after
starch intake but fell after
protein consumption. Additionally he demonstrated the unrestricted intestinal absorption of fats in diabetics. He thus contributed to the scientific basis for a diabetic diet. For diagnosis he proposed to measure sugar levels at specific, regular intervals: in the morning before breakfast and after meals. He thus anticipated modern principles of blood sugar measurements. Elsewhere he investigated the
laxative qualities of
lactose.
Theory of fermentation Traube's main work, the
Theorie der Fermentwirkungen (1858) is the first comprehensive theory of
fermentation to be based on experiments and elaborated consequently from the chemical point of view. The discovery in 1837 that
yeast was a living organism suggested that fermentation itself was a living process. Only a few scientists rejected this
vitalistic protoplasm theory, notably Traube. He was the first to define
enzymes as specific protein-like compounds and to formulate the necessity of direct molecular contact between enzyme and
substrate for fermentation to occur. He classified enzymes by reaction type, much as is done today. Long before
Eduard Buchner discovered
non-cellular fermentation in 1897, Traube isolated an enzyme from potatoes which could turn
guaiacum blue, thus demonstrating the continued efficacy of plant enzymes after they had been extracted from the cell. Until recently, biochemical history has not noted that Traube began to investigate the
kinetics of reactions and also demonstrated a reciprocal relationship between reaction time and quantity of enzyme. To defend his theory, Traube had to argue vigorously against
Louis Pasteur and
Felix Hoppe-Seyler. He contradicted Pasteur's assertion that fermentation could not occur without vital activity. In the context of these experiments Traube became the first to describe a process for making pure yeast. His differences with Hoppe-Seyler had to do with the mechanism by which oxygen was activated in fermentation reactions. Traube's experiments were designed to demonstrate activation via enzymes as catalysts and refute Hoppe-Seyler's hypothesis of
oxygen activation by nascent hydrogen produced by enzymes.
Physiology of plants and the invention of artificial semipermeable membranes In 1864 Traube was the first to produce artificial
semipermeable membranes, recognizing them as
molecular sieves and using them in developing the first physical-chemical theory of plant cell growth. The artificial cells were created by putting droplets of glue in
tannic acid; these grew under infusion of water. (Other membranes were created with tannic acid plus
verdigris or
potassium ferrocyanide plus
copper chloride). These membranes laid the foundation for research into osmotic pressure in solutions (
Wilhelm Pfeffer and
Jacobus Henricus van 't Hoff used them), and Traube himself did research on the manifestations of
diffusion and
osmosis.
Pathophysiology, bacteriology and hygienics Traube also made an important contribution to the study of the etiology of disease. Together with Gscheidlen, an assistant of
Rudolf Heidenhain he was the first to demonstrate via animal experiments that the organism has the ability to eliminate
putrefactive bacteria. In evaluating the results, he distinguished chemical poisoning from infection with microorganisms on the one hand, and
pathogenic from putrefactive bacteria on the other. Further, he was the first to propose a relation between
immune system to
infections and active oxygen in the blood cells. In his last work Traube proposed disinfecting drinking water with
calcium chloride. This technique became very important. By 1914 the method was used in more than 100 cities in America. It was reintroduced to Germany after World War II via the American occupation.
Biological oxidation Traube developed a homogeneous concept of the critical significance of
cellular respiration for the generation of heat, formation and maintenance of structures and organ function. From his point of view biological oxidation takes place not only in the blood but in all tissues. Traube's theory of muscular metabolism is significant because it showed the close relationship between respiration, muscular activity and heat generation, thus contributed to the refutation of Liebig's theory of nutrients. The substrates for creating muscle power were thus primarily nitrogen-free compounds and not just proteins. To investigate the process of enzymatic oxygen activation in organisms Traube did experimental research into inorganic
autoxidation and oxygen activation. He thus demonstrated the role of water as active partner in slow oxidations and showed the intermediate character of
hydrogen peroxide generation. == Accolades and appreciations ==