Deoxyribo nucleic acid synthesis

Howie JA, Gale GR. Cis-dichlorodiammine platinum II persistent and selective inhibition of deoxyribo-nucleic acid synthesis in vitro. Biochem Pharmacol 1970 19 21S1-2162. 

Pentose sugars are required for the synthesis of nucleic acids. Ribose 5-phosphate is utilized in the synthesis of purine and pyrimidine deoxyribo- and ribo-nucleotides. Since neonatal and fetal thymuses are highly active in nucleic acid synthesis, these tissues have an active pentose phosphate pathway to furnish ribose 5-phosphate. Ribose moieties also feature in the structure of major coenzymes such as NAD(P), coenzyme A and FAD (Figure 5.3). The degradation of nucleic acids and nucleotides... 

Polynucleotide polymerases, or nucleotidyl transferases, are enzymes that catalyze the template-instructed polymerization of deoxyribo- or ribonu-cleoside triphosphates into polymeric nucleic acid - DNA or RNA. Depending on their substrate specificity, polymerases are classed as RNA- or DNA-dependent polymerases which copy their templates into RNA or DNA (all combinations of substrates are possible). Polymerization, or nucleotidyl transfer, involves formation of a phosphodiester bond that results from nucleophilic attack of the 3 -OH of primer-template on the a-phosphate group of the incoming nucleoside triphosphate. Although substantial diversity of sequence and function is observed for natural polymerases, there is evidence that many employ the same mechanism for DNA or RNA synthesis. On the basis of the crystal structures of polymerase replication complexes, a two-metal-ion mechanism of nucleotide addition was proposed [1] during this two divalent metal ions stabilize the structure and charge of the expected pentacovalent transition state (Figure B.16.1). 

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