Pfizer Handbook of Microbial Metabolites 



534 



methylaminopurine and 2-methyladenine have been 

 found in bacterial RNA.^° 



CH3 

 NH 



H H 



6-Methylamino- 6-Dimethylamino- 

 purine purine 



OH 



CH;,— NH H 



2-Methylamino-6- 

 hydroxy purine 



NH, 



CH,— NH 



^N^^N- 

 H2N H 



1-Methylguanine 



-N^^N^ 

 CH3' H 



2-Methyladenine 



Kinetin is a substance isolated from yeast which stim- 

 ulates cell division in plant tissues. Work on kinetin and 

 related compounds has been reviewed. ^^ 



Several antibiotics contain the purine nucleus. Some 

 of these have excited interest as purine analogues for 

 tumor inhibition, but they are all toxic. Puromycin is 

 an inhibitor of protein synthesis. - The interference has 

 been shown to occur at the last stage — that is the ex- 

 change of the activated amino acid between transfer- 

 RNA and the growing protein chain. 



3f'J. W. Littlefield and D. B. Dunn, Biochem. J. 68 8P (1958); 

 idem.. Nature 181 254 (1958). 



2^ E. R. Squibb Lectures on Chemistry of Microbial Products, "Top- 

 ics in Microbial Chemistry," John Wiley and Sons, New York, 1958, 

 F. M. Strong, Kinetin and kinins, pp. 98-158. 



"-Michael Yarmolinsky and Gabriel de la Haba, Chem. and Eng. 

 News April 25, 1960. 



