Introduction* 



Motto: «De fixer les objets longtemps sans etre fatigue.» 



General remarks about our methods and their applications 



As a co-worker of Emil Fischer, I prepared the first optically active peptides in 

 the years from 1903 to 1906, and thereby, as one who belonged to the inner 

 circle of his co-workers, I came to know the methods and experimental techniques 

 of this greatest organic chemist of our times. Later on I began work on the quan- 

 tum requirement of photosynthesis in the radiation laboratory of the Physikalisch- 

 Technische Reichsanstalt, where my father Emil Warburg was president from 

 1906 to 1922. From the experiments of this laboratory, Max Planck derived his 

 law of radiation and calculated "the quantum of action", h = 6.55 • 10~ 2T erg ■ sec. 

 In the same laboratory Emil Warburg measured the first quantum yields of 

 photochemical reactions. 



Thus it came about that in the Kaiser- Wilhelm- Institut für Zellphysiologie the 

 methods of two widely separated fields, those of radiation physics and organic 

 chemistry, were united in one hand. The result was the elucidation of the chemical 

 mechanism of enzyme action — the very fast intermediate reactions of protein- 

 bound active groups, that we were able to separate from the enzymes and to cry- 

 stallize. Coenzymes and many vitamins proved to be nothing eise than free active 

 groups of enzymes. 



Here are some examples to illustrate the interplay of physical and chemical 

 methods that is characteristic of our institute. 



By the methods of radiation physics the substance was discovered, that reacts in 

 the living world with the molecular oxygen. By the methods of organic chemistry 

 this substance which is an iron Compound was isolated and crystallized. — By the 

 methods of radiation physics the acting groups of the hydrogen-transferring enzy- 

 mes were discovered, by the methods of organic chemistry these acting groups were 

 separated and crystallized. — From the interaction of the oxygen- and hydrogen- 

 transferring enzymes resulted the respiratory chain — the general Solution of the 

 problem of Lavoiser's respiration. — By the methods of radiation physics the main 

 reaction of fermentations was recognized as a hydrogen transfer by nicotinamide, 

 by the methods of organic chemistry 1, 3, Diphosphoglyceric acid has been iso- 

 lated from yeast, the reactions of which explain the production of phosphateenergy 

 in fermentations. — By methods of physics the fermentation of Cancer cell was 

 discovered and the de-differentiated growth of Cancer cells was explained by a 

 type of energy transformation at a time when the atmosphere of the earth did not 

 yet contain oxygen — a result, which explained the ultimate cause of Cancer by the 

 anaerobic past of life. 



* The italicized figures in this introduction are the reference numbers of the papers listed in the 

 previous table of contents. 



* Other literature references (superscripts) are quoted in this introduction only when older 

 works of the author or works of other authors are being cited. 



