Adenosine metabolism in human erythrocytes: a study of some factors which affect the metabolic fate of adenosine in intact red cells in vitro

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Adenosine deaminase | Blood and hemopoietic system

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Title: Adenosine metabolism in human erythrocytes: a study of some factors which affect the metabolic fate of adenosine in intact red cells in vitro
Author(s): Hawkins, Christopher F.; Kyd, Jennelle M.; Bagnara, Aldo S.
Abstract: Adenosine metabolism was studied in intact human erythrocytes over a range of adenosine and intracellular phosphate concentration. The concentration of adenosine greatly influenced its partition between deamination via adenosine deaminase (EC 3.5.4.4) and phosphorylation via adenosine kinase (EC 2.7.1.20). For example, for cells incubated in a medium containing 1 mM phosphate, a single addition of 40 μM adenosine was largely deaminated (91% deaminated, 9% phosphorylated). Adenosine added to the incubation at lower concentration (0.5 μM) was largely phosphorylated (81% phosphorylated, 19% deaminated). This partition could be predicted from the known K(m) and V parameters of the kinase and deaminase reactions. Intracellular phosphate concentrations also affected the metabolism of adenosine, apparently by stimulating adenosine kinase activity in situ. The ratio of adenosine phosphorylated to adenosine deaminated was increased significantly by increases in the intracellular phosphate concentration. Thus, at 4 μM adenosine, approximately 30% of the adenosine was phosphorylated when the intracellular phosphate concentration was 1 mM. However, when the intracellular phosphate concentration was increased to 7.5 mM, the proportion of 4 μM adenosine phosphorylated increased to 70%. Our studies also revealed that the kinase was inhibited by high adenosine concentrations, especially when 50-100 μM adenosine was added to the incubation.
Publication type: Journal article
Source: Archives of Biochemistry and Biophysics, Vol. 202, no. 2 (Jul 1980), pp. 380-387
Publication year: 1980
FOR Code(s): 0601 Biochemistry and Cell Biology
Keyword(s): Adenosine; Adenosine deaminase; Adenosine kinase; Blood and hemopoietic system; Drug metabolism; Erythrocytes; Metabolism; Pharmacokinetics; Phosphorylation; Radioisotope
Publisher: Academic Press
ISSN: 0003-9861
Publisher URL: http://dx.doi.org/10.1016/0003-9861(80)90441-5
Peer reviewed