PREFACE 



whole new industry has sprung up which provides practically 

 every important biochemical compound relatively inexpensively 

 and of high purity. The importance of this development to the 

 rapid progress of biochemical research cannot be underesti- 

 mated. 



Enzymology has indeed prospered by application of new 

 methodological tools but the traffic has gone both ways. In 

 turn, the enzymes have proved to be tools of such breath-taking 

 elegance and simplicity as to revolutionize the tactics of deter- 

 mining structure or of analyzing for minute amounts of material. 

 The elucidation of the structure of nucleic acid, of nucleotides, 

 and of various nucleotide cofactors has been accomplished 

 principally, if not exclusively, by enzymatic procedures and 

 with relatively small amounts of compound. 



The current procedures for isolating enzymes are still 

 largely classical, but signs are multiplying that big changes in 

 methodology are imminent. Chromatography on columns of 

 cellulose derivatives or of calcium phosphate, electroconvection, 

 starch and filter paper electrophoresis, ion exchange resin 

 chromatography, and partition methods are portents of the 

 things to come. 



In recent years there has been a growing recognition of the 

 role of integrated enzyme systems in cellular processes. The 

 concept of the mitochondrion as an organized mosaic of several 

 hundreds of enzymes linked together structurally as well as 

 functionally and with unique operational principles is now well 

 established in biochemical thinking. It is only in terms of large 

 molecular aggregates and of enzymes bonded together in a 

 precise pattern that it is at all possible to approach problems such 

 as oxidative phosphorylation, electron transfer, and muscular 

 contraction. The organized enzyme systems have provided the 

 bridge between classical enzyme chemistry and cellular proc- 

 esses. In addition to the mitochondrion, other functional 

 particles have been described such as the chloroplast in photo- 

 synthesis, and microsomes and nuclei in protein synthesis. 



Progress in the field of the physical chemistry of biological 



viii 



