Nucleic Acids in Chemistry and Biology
Early syntheses of nucleoside phosphate esters worked mainly with mild condensing agents such as dicy- clohexylcarbodiimide (DCC ...
(MSNT). A mixed phosphoryl–sulfonyl anhydride is produced initially, in which the methyl groups of the mesitylene ring provide s ...
intermediates do not require further protection at phosphorus and are rapidly and efficiently activated by a range of condensing ...
group may be achieved using bulky phosphorylating agents such as bis-(2,2,2-trichloro-1,1-dimethyl) phos- phorochloridate (Figur ...
(Ap 4 A) and other polyphosphates such as Ap 3 A (Figure 3.63) are stable minor nucleotide species found in low concentration in ...
biosynthesis involves the condensation of ATP with a monoalkyl phosphate, and the pyrophosphate appears to act generally as a st ...
A related but more general route to nucleoside 5-triphosphates or ,-substituted analogues thereof involves the reaction of an ...
All of these methods produce nucleotide phosphorothioates as racemic mixtures, although the diastereoiso- mers can generally be ...
3.4 Biosynthesis of Nucleotides Nucleotides play a key role as the precursors of DNA and RNA, as activated intermediates in many ...
reaction catalysed by the enzyme ribose phosphate pyrophosphokinase (Figure 3.71). ATP acts as the donor of pyrophosphate while ...
or ammonia. The leaving group can be inorganic phosphate, pyrophosphate or AMP, while the displacing nucleophile can be ammonia, ...
is inhibited by the final product of the pathway. For example, the enzyme ribose phosphate pyrophospho- kinase (Figure 3.71) is ...
synthesis of carbamoyl phosphate is inhibited by UMP. In the next step, the pyrimidine ring is formed by cyclization and loss of ...
a result of hydrolysis of DNA or RNA. In a similar way as in the salvage of purines, phosphorylases catal- yse nucleoside format ...
predominant dioxopyrimidine nucleotide incorporated into DNA. First, deoxythymidine 5-monophosphate (dTMP) is biosynthesised fr ...
Nucleosides and Nucleotides 123 N HN N N H O N H 2 N HN N N H O N H HN N N H O O N HN N N H O N H HN H N N H O O O GMP adenosine ...
deaminase to IMP and adenosine is deaminated to inosine by adenosine deaminase, an enzyme that is thought to be present in eleva ...
are unique to retroviruses and they are also tolerant to a wide range of nucleoside triphosphate analogues, which identifies the ...
The following section will focus on antimetabolites while parts of Chapters 8 and 9 will deal with other chemotherapeutic agents ...
dNTPs required for DNA synthesis. However, the mechanisms by which these drugs achieve selectivity for their target cells are no ...
«
3
4
5
6
7
8
9
10
11
12
»
Free download pdf