4 A. TISELIUS 



recall a conversation I had with a distinguished elderly professor of 

 organic chemistry when I was a young man and found myself gradually 

 drifting from physical chemistry into biochemistry. "Be careful," he said, 

 "this is a dangerous subject, and you will never become a good bio- 

 chemist anyhow. What is the use of studying enzymes and the mechanism 

 of their action until the phenomena of catalysis have been analyzed and 

 elucidated by the physical chemists ?" I have always doubted whether he 

 was right in this, and today I doubt it still more. I do not propose to say 

 that the biochemists can get much further than the physical chemists in 

 providing the ultimate explanation for these and similar phenomena, but 

 I do believe that they have brought to light a number of observations 

 which must be of fundamental importance in any attempt to work out a 

 general theory of catalytic function in the inorganic world. Thus the 

 study of the functions of substances of complicated structure — such as we 

 find in biological materials — may contribute just as much, or even more, 

 to our basic knowledge in the field in general as a study confined only to 

 the very simplest inorganic reactions. It would appear natural that this 

 should be so: the phenomena of catalysis which we meet in biological 

 matter are among the most striking and most specific found in Nature. 

 Thus, quite aside from their interest per se, it must be worth while to 

 study them from a very general and advanced point of view. 



Discussion of function on a molecular level usually involves mechanisms 

 of activation and the structural background of highly specific affinities. 

 This is of course the case when we deal with reactions between, for example, 

 a macromolecular enzyme and substrate molecule of smaller size. But it is 

 also true when we deal with those specific interactions between difi^erent 

 kinds of macromolecules which appear to play such an important role 

 in the organized chemical reactions characteristic of life. Here also, 

 structural aspects come into the picture and we then gradually find our- 

 selves discussing organization rather than intermolecular structures 

 without being able to define a borderline in the application of these terms. 

 This is also reflected in the methods used, where electron microscopy 

 goes hand in hand with methods of structure analysis such as X-ray 

 crystallography and organic chemistry have provided. I shall not dwell 

 upon this interesting field of "molecular biology", as this rather belongs 

 to the programme of the following days — especially the forthcoming dis- 

 cussion about structure and function of certain submicroscopic particles. 

 But I wish to emphasize that here again we have a field which is yielding 

 much new information of a very general importance — also to the chemists. 

 The elusiveness of the structures and functions involved in this highly 

 organized matter is of a kind where biologists and biochemists with their 

 gentle methods and somewhat greater reverence for Nature in its intact 

 forms are more likely to succeed than the chemists. 



