3. PRPP synthetase Nucleoside phosphorylases Phosphoribosyl transferases

5. The committed step of de novo purine nucleotide biosynthesis

6. Phosphoribosylamine synthase: cooperativity with respect to PRPP concentration & product inhibition

7. Outline of de novo purine nucleotide biosynthesis

13. Outline of de novo pyrimidine nucleotide biosynthesis

14. Enzymes I. Ribonucleotide reductase II. Nucleotide diphosphate kinase III. dCMP kinase IV. dUTP diphosphohydrolase V. dCMP deaminase VI. Thymidylate synthase VII. FH 2 reductase