Friday 19 October 2007
Both the salvage and de novo synthesis pathways of purine and pyrimidine biosynthesis lead to production of nucleoside-5’-phosphates through the utilization an activated sugar intermediate and a class of enzymes called phosphribosyltransferases.
The activated sugar used is 5-phospho—D-ribosyl-1-pyrophosphate, PRPP: PRPP is generated by the action of PRPP synthetase and requires energy in the form of ATP as shown:
ribose-5-phosphate + ATP -------> PRPP + AMP
This reaction releases AMP. Therefore, 2 high energy phosphate equivalents are consumed during the reaction.