FIG. 1.

Overview of the nucleotide metabolism of L. lactis. Purine and pyrimidine metabolism is shown to the left and right of the figure, respectively. Only the interconversions of the deoxyribonucleotide pyrimidines and precursors are shown in detail. Other reaction arrows may comprise more than one enzymatic reaction. All genes indicated have been localized in the genome of L. lactis IL1403, except ndk and dcd (7). In the IL1403 genome sequence tdk is referred to as yfiG and tmk is referred to yeaB. Genes: deoB, phosphopentomutase; deoC, deoxyriboaldolase; pdp, thymidine phosphorylase; cdd, cytidine deaminase; tdk, thymidine kinase; dcdA, dCMP deaminase; thyA, TS; cmk, CMP kinase; dut, dUTPase; tmk, thymidylate kinase; ndk, NDP kinase; dcd, dCMP deaminase. PRPP, 5-phosphoribosyl-1-pyrophosphate.