摘要: Ribonucleotides (NTP) and deoxyribonucleotides (dNTP) are the basic building blocks of RNA DNA. While major nucleotides found in all mammalian cells their relative pool sizes quite different depending on cell type species. These unique nucleotide patterns maintained to a large extent, by tightly regulated biosynthetic metabolic pathways through number feedback controls. Disruption these balances have been shown profound effects DNA synthesis replication cultured (Ashman Davidson 1981; Topal Baker 1982; Das et al. 1983; Newman Miller Meuth 1984; Nicander Reichard 1985; Yosmoka 1987; Phear 1989; Kohalmi 1991; Wataya 1993). In fact, this biological feature has become fundamental tenet for design chemotherapeutic agents past half century.