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Cytosine biosynthesis is a two-step reaction which involves the conversion of UMP to UTP. Phosphate addition to UMP is catalyzed by a kinase enzyme. The enzyme CTP synthase catalyzes the next reaction step: the conversion of UTP to CTP by transferring an amino group from glutamine to uridine; this forms the cytosine base of CTP. [21]
Cytosine (/ ˈ s aɪ t ə ˌ s iː n,-ˌ z iː n,-ˌ s ɪ n / [2] [3]) (symbol C or Cyt) is one of the four nucleotide bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group ...
[1] [2] [3] This enzyme catalyses the following chemical reaction. S-adenosyl-L-methionine + cytosine 967 in 16S rRNA S-adenosyl-L-homocysteine + 5-methylcytosine 967 in 16S rRNA. The enzyme specifically methylates cytosine 967 at C 5 in 16S rRNA.
RNA is composed of pyrimidine and purine nucleotides, both of which are necessary for reliable information transfer, and thus natural selection and Darwinian evolution. Becker et al. showed how pyrimidine nucleosides can be synthesized from small molecules and ribose , driven solely by wet-dry cycles.
It is the rate-limiting enzyme for the synthesis of cytosine nucleotides from both the de novo and uridine salvage pathways. [ 4 ] The reaction proceeds by the ATP-dependent phosphorylation of UTP on the 4-oxygen atom, making the 4-carbon electrophilic and vulnerable to reaction with ammonia. [ 5 ]
Nucleic acid metabolism is a collective term that refers to the variety of chemical reactions by which nucleic acids (DNA and/or RNA) are either synthesized or degraded. Nucleic acids are polymers (so-called "biopolymers") made up of a variety of monomers called nucleotides.
The major difference between the two molecules is the base used, which in CTP is cytosine. CTP is a substrate in the synthesis of RNA . CTP is a high-energy molecule similar to ATP, but its role as an energy coupler is limited to a much smaller subset of metabolic reactions.
Both RNA and DNA contain two major purine bases, adenine (A) and guanine (G), and two major pyrimidines. In both DNA and RNA, one of the pyrimidines is cytosine (C). However, DNA and RNA differ in the second major pyrimidine. DNA contains thymine (T) while RNA contains uracil (U). There are some rare cases where thymine does occur in RNA and ...