468 



E. A. EVANS, JR. 



the nucleic acid of the T-even series), together with varying quantities of 

 glucose, presumably attached to the 5-HMC. This pyrimidine, which has not 



TABLE II 

 Composition of Coliphage DNA 



« Wyatt and Cohen (1953). 

 '=LwofI(1953). 



^ Knight and Fraser (Knight, 1954). 

 ^ Mackal and Meyer (1957). 



* Lunan and Sinsheimer (1956). 



been found in any other naturally occurring material, is not present in the 

 odd-numbered T phages and, so far as is known, these do not contain any 



I 



CHjOH 



5-HYOROXYMETHYL CYTOSINE 

 DECXYRIBOSIDE 



N = 



= C 



I 



N 



I 

 HC 



I 

 HCH 



HCOH 



= C — NHi 



I 

 C — CHjO 



II I 

 -CH HC O 



I 

 - O HCOH 



I 

 HOCH 



I 

 HCOH 



HC- 



HC- 



I 



CH2OPO3H CH2OH 



5-glucosyl hydroxymethyl cytosine 

 deoxynucleotide 



Fig. 2. 



comparable purine or pyrimidine bases. The presence of 5-HMC was ifirst dis- 

 covered by Wyatt and Cohen in 1952. The nature of the compound was demon- 

 strated by its isolation in sufficient quantities for analysis and by direct 



