deoksiadenosine

Deoxyadenosine, also called 2′-deoxyadenosine, is a deoxyribonucleoside formed by an adenine base attached to a deoxyribose sugar via a β-N9 glycosidic bond. It is one of the nucleosides that comprise the classical DNA building blocks and serves as the nucleoside counterpart to the deoxyribonucleotide dAMP when phosphorylated.

In cellular metabolism, deoxyadenosine can be phosphorylated by deoxyadenosine kinase to form deoxyadenosine monophosphate (dAMP), which can be further converted to dADP and dATP. The accumulation of dATP is particularly significant because it inhibits ribonucleotide reductase, an enzyme essential for de novo DNA synthesis, leading to impaired DNA replication and potential cytotoxic effects. The balance of deoxyadenosine and its phosphorylated forms is therefore important for nucleotide pool regulation and cell viability.

Adenosine deaminase (ADA) acts on both adenosine and deoxyadenosine, converting them to inosine and deoxyinosine, respectively, as part of purine catabolism. ADA deficiency disrupts this pathway and can result in marked accumulation of deoxyadenosine and dATP, which is toxic to lymphocytes and leads to severe combined immunodeficiency (SCID). Management strategies for ADA deficiency include enzyme replacement therapy, hematopoietic stem cell transplantation, and gene therapy.

Deoxyadenosine occurs endogenously from DNA turnover and can be obtained/examined in research settings to study purine metabolism and nucleotide salvage pathways.