PROBLEMS IN THE STUDY OF MULTIPLE 



ENZYME SYSTEMS 



G. ROBERT GREENBERG, Department of Biochemistry, School of 

 Medicine, Western Reserve University, Cleveland, Ohio 



Many over-all pathways of biosynthesis of cellular constitu- 

 ents have been outlined in recent years. It is obvious that the 

 resolution of these pathways into discrete reaction mechanisms 

 ultimately depends on using in vitro systems and requires all the 

 techniques of biochemistry. Yet in many instances the con- 

 cepts which help in approaching such problems are quite ele- 

 mentary. In studies of multiple enzyme systems certain factors 

 and ideas have repeatedly entered into our reasoning. Al- 

 though a good part of the thinking involved is not entirely 

 quantitative, it may nevertheless provide an approach to the 

 problem. Accordingly I should like to bring together some of 

 these ideas at the risk of outlining concepts which belong to the 

 everyday vocabulary of the more sophisticated and with the 

 hope that others may be stimulated to undertake a thorough 

 organization of this subject. Many of the important problems 

 concerned with multi-enzyme systems such as the energetics of 

 coupled reactions, kinetics, and the use of inhibitors have not 

 been included. I hope therefore that these paragraphs will be 

 considered as a reflection of some of our experiences and will be 

 clearly distinguished from a brief do-it-yourself pamphlet. 



537 



