International Scientific Vocabulary cyt- + -ose + 2-ine
First Known Use: 1894
Medical Definition of CYTOSINE
: a pyrimidine base C4H5N3O that codes genetic information in the polynucleotide chain of DNA or RNA—compare adenine, guanine, thymine, uracil
Illustration of CYTOSINE
Organic compound of the pyrimidine family, often called a base, consisting of a single ring, containing both nitrogen and carbon atoms, and an amino group. It occurs in combined form in nucleic acids and several coenzymes. In DNA its complementary base is guanine. It or its corresponding nucleoside or nucleotide may be prepared from DNA by selective techniques of hydrolysis.