2Deoxyadenosine

2'-Deoxyadenosine, commonly abbreviated as dAdo, is a deoxyribonucleoside consisting of adenine attached to a 2'-deoxyribose sugar via a beta-N9-glycosidic bond. It is one of the four standard deoxyribonucleosides that comprise DNA, the others being deoxyguanosine, deoxycytidine, and thymidine.

In DNA, the deoxyribose is the sugar component, and the nucleoside forms the backbone of the DNA strand, with adenine pairing with thymine through two hydrogen bonds in double-stranded regions. As a nucleoside, deoxyadenosine is a building block that contributes to the genetic information stored in DNA and to DNA replication and repair processes carried out by polymerases.

Biosynthesis and metabolism: Deoxyadenosine can be generated and recycled within cells through nucleotide salvage pathways. It is phosphorylated by specific kinases to deoxyadenosine monophosphate (dAMP), and then further converted to dADP and dATP, which serve as substrates for DNA synthesis. Deoxyadenosine can also be deaminated by adenosine deaminase to deoxyinosine, a step in nucleotide catabolism. Deficiency of adenosine deaminase leads to accumulation of dATP, which can inhibit ribonucleotide reductase and impair lymphocyte development, a condition known as severe combined immunodeficiency.

See also: deoxyguanosine, deoxycytidine, thymidine.