Uratsiili

Uratsiili (uracil) is a pyrimidine nucleobase that serves as one of the four nucleobases in ribonucleic acid (RNA). Its chemical formula is C4H4N2O2, and it consists of a six-member ring with two carbonyl groups at positions 2 and 4, classifying it as a pyrimidine-2,4-dione. Uratsiili pairs with adenine in RNA through two hydrogen bonds, helping encode genetic information during transcription and translation. In DNA, thymine substitutes for uratsiili, providing greater resistance to spontaneous cytosine deamination.

Biosynthesis and metabolism: Uratsiili is produced in cells via de novo pyrimidine biosynthesis and can be salvaged via uracil phosphoribosyltransferase to UMP. In mammals, uratsiili is degraded via the dihydropyrimidine pathway to beta-alanine, carbon dioxide, and ammonia.

Occurrence and applications: Uratsiili is abundant in cellular RNA across organisms and is not used in DNA. In molecular biology, uracil derivatives such as dUTP are used in certain protocols; enzymes like uracil-DNA glycosylase can remove uracil from DNA, enabling contamination control in PCR workflows.