Biochemical basis for differential deoxyadenosine toxicity to T and B lymphoblasts: role for 5'-nucleotidase.
AUTOR(ES)
Wortmann, R L
RESUMO
Deoxyadenosine metabolism was investigated in cultured human cells to elucidate the biochemical basis for the sensitivity of T lymphoblasts and the resistance of B lymphoblasts to deoxyadenosine toxicity. T lymphoblasts have a 20-to 45-fold greater capacity to synthesize deoxyadenosine nucleotides than B lymphoblasts at deoxyadenosine concentrations of 50--300 micron. During the synthesis of dATP, T lymphoblasts accumulate large quantities of dADP, whereas B lymphoblasts do not accumulate dADP. Enzymes affecting deoxyadenosine nucleotide synthesis were assayed in these cells. No substantial differences were evident in activities of deoxyadenosine kinase (ATP: deoxyadenosine 5'-phosphotransferase, EC 2.7.1.76) or deoxyadenylate kinase [ATP:(d)AMP phosphotransferase, EC 2.7.4.11]. The activity of 5'-nucleotidase (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) was increased 44-fold for AMP and 7-fold for dAMP in B lymphoblasts. A model for the regulation of deoxyadenosine nucleotide synthesis by 5'-nucleotidase activity is proposed on the basis of the observations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=383616Documentos Relacionados
- Deoxyadenosine triphosphate as a mediator of deoxyguanosine toxicity in cultured T lymphoblasts.
- Purification and properties of human erythrocyte pyrimidine 5'-nucleotidase.
- Purinogenic Immunodeficiency Diseases: DIFFERENTIAL EFFECTS OF DEOXYADENOSINE AND DEOXYGUANOSINE ON DNA SYNTHESIS IN HUMAN T LYMPHOBLASTS
- Hydrolysis of bis(5'-nucleosidyl) polyphosphates by Escherichia coli 5'-nucleotidase.
- Effect of surface modifiers on an ectoenzyme: granulocyte 5'-nucleotidase.