Nucleoside Di- and Triphosphoric Acids

In 1928 Lohmann isolated a compound from muscle tissue extracts which consisted of adenosine esterified with 3 moles of phosphoric acid (127). Acid hydrolysis of the adenosine triphosphate (ATP) yielded 1 mole of adenine, 1 mole of ribose monophosphate, and 2 moles of phosphoric acid, whereas neutral hydrolysis gave adenosine 5 -phosphate (muscle adenylic 

ATP has been shown to react with carboxylic acids (133c), amino acids (133d), and sulfate (133e) in the presence of the appropriate enzyme system to yield biologically active mixed anhydrides of AMP plus pyrophos- 

The elegant ion-exchange separation techniques evolved in the recent years have enabled investigators to isolate from yeast, bacteria, and animal tissues, uridine 5 -di- (UDP) and -triphosphates (UTP) (134)y cytidine 5 -di- (CDP) and -triphosphates (CTP), and guanosine 5 -di- (GDP) and -triphosphates (GTP) (135), Application of the synthetic approaches developed for ADP and ATP has permitted the ready synthesis of uridine 5 -di- and -triphosphates (136) and could be applied to the other two pairs of nucleotides (CDP, CTP GDP, GTP). Although the functions of these latter compounds have not been elucidated, it seems probable that they are involved as coenzymes in transphosphorylation reactions similar to ATP. 

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