Figure 11.

Potential mechanism for 6MMPr effects on nucleobase and purine nucleoside conversion to the relevant triphosphate forms. 6MMPr inhibits phosphoribosyl pyrophosphate amidotransferase (PPAT) resulting in an inhibition of de novo purine synthesis. PPAT inhibition causes PRPP accumulation and increases nucleobase conversion to the ribonucleoside-5′-monophosphate form by cellular phosphoribosyltransferases and kinases. Green arrows pointing upwards indicate an increased accumulation and red arrows pointing downwards a decreased accumulation.