Ribose 5-phosphate ②AMP ribose 8←-GMP- The de novo synthesis ofaMP and gmp PRPP 6+-AMP glutamine-PRPP⑧GMP is regulated mainly ⑧←IMP by sequential feedback 5-Phosphoribosy lamine Inhibition IMP IMP synthetase dehydrogenase AMP- ←GMP-、 XMP XMP glutamine Adenylos GME AMPThe de novo synthesis of AMP and GMP is regulated mainly by sequential feedback Inhibition