GENETIC CONTROL OF CELL INTEGRATION 



325 



bination of TMG and phenyl galactoside, neither of which will support 

 growth alone. 



Comparative studies of the binding affinities for different galactosides 

 and of the immunological specificity of purified preparations of /3-galac- 

 tosidase, produced after induction by various inducers, have revealed 

 no differences among them. Within the sensitivity limits of the methods 

 employed, these results show that the inducer does not confer any speci- 

 ficity upon the induced enzyme. Since it is usually possible to detect a 



CH2OH 



Inducer 



Substrate 



CH2OH 



S— CH3 



FIGURE 11.9. Galactosides and thiogalactosides as inducers of /3-galactosidase and 

 as substrates of that enzyme in f. co// (from Monod, 1956, Enzymes: Unifs of Biological 

 Structure and Function, New York, Academic Press, pp. 7-28). 



