Purine Ribonucleoside and Deoxyribonucleoside Metabolism in Thymocytes
The human deficiencies of adenosine deaminase and purine nucleoside phosphorylase activities are associated with an accumulation of the purine deoxyribonucleoside triphosphates, dATP (1–4) and dGTP (4) respectively. In the absence of adenosine deaminase or purine nucleoside phosphorylase activities, deoxyadenosine or deoxyguanosine are presumed to be rephosphorylated, thereby producing increased dATP or dGTP concentrations which may in turn inhibit ribonucleotide reductase. We have therefore examined the specificity and optimal assay conditions for the principal purine ribonucleoside and deoxyribonucleoside kinase activities in mouse thymocytes. The role of these activities was evaluated by analyzing the competition for common substrates between the nucleoside kinases and adenosine deaminase or purine nucleoside phosphorylase.
KeywordsAdenosine Deaminase Purine Nucleoside Purine Nucleoside Phosphorylase Mouse Thymocyte Optimal Assay Condition
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