COFACTORS OF EnZYMIC ADAPTATION 



Table V 



Promutagenic action of Cofactor T 



219 



Conditions: Adenine: 0-15 mg./ml. 



Source of cofactor: commercial threose 1 mg./ml. 



Table VI gives a list of substances assayed to verify whether 

 the effect of E can be duplicated with something else. All 

 were found inactive. For the sake of comparison two results 

 obtained with synthetic derivatives of pure D-erythrose are in- 

 cluded. The actual amount of the derivative is unknown and is 

 probably much smaller than the quantity of the sugar of origin. 



Euflavine is a very reactive dye that forms readily additive 

 complexes with a great number of substances (nucleic acids, 

 proteins, deoxyribonucleotides etc. ; cf. Peacocke and Skerrett, 

 1955). 



Is it not possible that the interaction of purines and 

 cofactors with euflavine is a chemical combination occurring 

 in vitro outside the cells, and bearing no relation to the cellular 

 receptors? This question can be answered in a negative way, 

 for the following reasons : 



{a) The complex formation in vitro could easily explain the 

 action of E but only with difficulty the action of T. 



