THE SIGNIFICANCE OF INDUCED ENZYME 



FORMATION* 



S. SPIEGELMAN and A. M. CAMPBELL, f Department of 

 Bacteriology, University of Illinois, Urbana, Illinois 



Introduction 



It is no historical accident that a renewed interest in the 

 phenomenon of "enzymatic adaptation" came hard on the heels 

 of the explosive birth of modern microbial genetics. Two good 

 reasons can be advanced for this virtual concurrence. In the 

 first place, the work with Neurospora, yeast, and the bacteria 

 provided the genetically controlled material necessary for bio- 

 logically intelligent and interpretable experiments. Secondly, 

 from its very inception, microbial biochemical genetics posed 

 the gene-enzyme problem in terms of a rapidly accumulating 

 multitude of experimental facts which could not be ignored. 

 Their existence demanded an immediate search for tools which 

 would permit the experimental analysis of such statements as 

 "genes control enzymes." 



There were two obvious directions which a quest of this na- 

 ture could, and did, take. One started with the gene and led to 



* The original experiments reported here from the authors' laboratory 

 were supported by grants from the National Cancer Institute of the U. S. 

 Public Health Service and the Office of Naval Research. 



t Present address: Department of Bacteriology, University of Michigan 

 Ann Arbor, Michigan. 



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