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BIOCHEMICAL BASIS FOR DIFFERENTIAL DEOXYADENOSINE TOXICITY TO LYMPHOBLAST-T AND LYMPHOBLAST-B - ROLE FOR 5'-NUCLEOTIDASE

BIOCHEMICAL BASIS FOR DIFFERENTIAL DEOXYADENOSINE TOXICITY TO LYMPHOBLAST-T AND LYMPHOBLAST-B - ROLE FOR 5'-NUCLEOTIDASE PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Wortmann, R. L., Mitchell, B. S., Edwards, N. L., Fox, I. H. 1979; 76 (5): 2434-2437

Abstract

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.

View details for Web of Science ID A1979GW30700076

View details for PubMedID 221924