The second Nobel Prize in Chemistry was awarded to Emil Fischer, who showed how establishing key relationships in biology can be a matter of finding the right chemistry. Fischer showed how piecing together intricate chemical details about substances in Nature that are essential for life can reveal vital information about their functions and uncover unexpected connections.
Fischer transformed our knowledge of carbohydrates, chemicals such as sugars and starch, which provide a major source of energy for animals. Notoriously difficult to purify and characterise, Fisher discovered that when sugars found in fruits react with the compound phenylhydrazine they form products that are easy to extract and examine. He identified the chemical composition of all the known sugars, from which he could create synthetically a range of increasingly complex sugars in the laboratory.
Natural fruit sugars might vary considerably in their physical characteristics, but Fisher discovered that many of them in fact share a strikingly similar chemical makeup to the common sugar, glucose. Applying the theories of three-dimensional chemistry developed by the first Nobel Laureate in Chemistry, Jacobus van ‘t Hoff, Fischer deduced that these sugars differ through the various ways in which their carbon, hydrogen and oxygen atoms are arranged in space. Creating a simple yet ingenious way in which to depict all these different arrangements on paper, he explained how Nature forms two types of sugars, the D sugars and the L sugars, that are mirror images of one another.
Through his refined methods of analysis and synthesis, Fischer also identified the chemical relationships between a range of biologically important chemicals, including caffeine, the stimulant in coffee, and uric acid, the cause of the disease gout. All these chemical siblings share a parental structure called a purine nucleus, and by pinpointing the differences in chemical structures around this nucleus, Fischer created an extended family of around 150 artificial derivatives of these substances in the laboratory, which provided strong evidence for how these chemicals are formed in Nature.