English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Accumulation of dATP derived from 2'-deoxyadenosine (dAdo), causing inhibition of ribonucleotide reductase and depletion of the other deoxynucleotide substrates required for DNA synthesis, has been suggested as the cause of the lymphopenia and immune defect in inheritable deficiency of adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4). dAdo also inactivates the enzyme S-adenosylhomocysteine hydrolase (AdoHcyase; S-adenosyl-L-homocystein hydrolase EC 3.3.1.1) which is involved in the catabolism of S-adenosyl-L-homocysteine (AdoHcy), both a product and a potent inhibitor of S-adenosylmethionine-dependent transmethylation. We have tried to determine whether inactivation of AdoHcyase might also contribute to dAdo toxicity to adenosine deaminase-inhibited cells. dAdo rapidly inactivates intracellular AdoHcyase and causes the accumulation of AdoHcy in WI-L2 human B lymphoblastoid cells. Low concentrations of adenosine (Ado), which block binding of dAdo to purified AdoHcyase, prevented inactivation of intracellular AdoHcyase and also lessened the growth-inhibitory effect of dAdo. A mutant of this cell line which lacks Ado kinase and accumulated endogenously synthesized Ado was resistant to the effects of dAdo on both growth and AdoHcyase activity. The mutant also accumulated far less dATP from dAdo than did its parent and was resistant to the inhibitory effect of dAdo on DNA synthesis, indicating the Ado kinase is involved in dAdo phosphorylation in these cells. Combinations of deoxycytidine, thymidine, and deoxyguanosine that could prevent dATP-mediated depletion of deoxynucleotide pools but not AdoHcyase inactivation were less effective than Ado in preventing dAdo toxicity to normal lymphoblasts. Our results suggest that inactivation of AdoHcyase, as well as dATP accumulation, contributes to dAdo toxicity.

proceedings of the national academy of sciences of the united states of america

Resistance of an adenosine kinase-deficient human lymphoblastoid cell line to effects of deoxyadenosine on growth, S-adenosylhomocysteine hydrolase inactivation, and dATP accumulation.