What is cytosine?

  • (noun): A base found in DNA and RNA and derived from pyrimidine; pairs with guanine.
    Synonyms: C


Cytosine (C) is one of the four main 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 at position 2). The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, it forms three hydrogen bonds with guanine.

Read more about Cytosine.

Some articles on cytosine:

Guanine - Basic Principles
... Guanine, along with adenine and cytosine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA, and uracil only in RNA ... It binds to cytosine through three hydrogen bonds ... In cytosine, the amino group acts as the hydrogen bond donor and the C-2 carbonyl and the N-3 amine as the hydrogen-bond acceptors ...
Cytosine - Chemical Reactions
... Cytosine can be found as part of DNA, as part of RNA, or as a part of a nucleotide ... In DNA and RNA, cytosine is paired with guanine ... Cytosine can also be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase or be methylated and hydroxylated to make 5-hydroxymethylcytosine ...
TRNA (cytosine-5-)-methyltransferase
... In enzymology, a tRNA (cytosine-5-)-methyltransferase (EC is an enzyme that catalyzes the chemical reaction S-adenosyl-L-methionine + tRNA S-adenosyl-L-h ... The systematic name of this enzyme class is S-adenosyl-L-methioninetRNA (cytosine-5-)-methyltransferase ... Other names in common use include transfer ribonucleate cytosine 5-methyltransferase, and transfer RNA cytosine 5-methyltransferase ...
Jurassic Park (novel) - Biological Issues and Accuracy
... The processes of CpG methylation and cytosine deaminization are especially important ... CpG methylation is a common regulatory device in eukaryotic DNA, where cytosine immediately preceding a guanine on the same strand is methylated ... The problem is, over time cytosine deaminization can occur—where a cytosine loses its amine group, which is replaced by a carbonyl group ...
Cytosine Deaminase
... In enzymology, a cytosine deaminase (EC is an enzyme that catalyzes the chemical reaction cytosine + H2O uracil + NH3 Thus, the two substrates of this enzyme are cytosine and H2O ... The systematic name of this enzyme class is cytosine aminohydrolase ...