title: The rate of the AMP/adenosine substrate cycle in concanavalin-A-stimulated rat lymphocytes.
abstract: The effect of adenosine on the metabolism of prelabelled adenine nucleotides was investigated in concanavalin-A-stimulated rat lymphocytes. Adenosine in the presence of the adenosine deaminase inhibitor, deoxycoformycin, caused a 2-fold increase in the ATP concentration. This effect was, in part, countereacted by an increased rate of adenine nucleotide catabolism, which could be explained by a stimulation of AMP deaminase (EC 3.5.4.6). At the same time a continuous rate of labelled adenosine production was found, which was not affected by the increased ATP concentration and which could only be detected by the trapping effect of a high concentration of added unlabelled adenosine. It is concluded that the rate of the substrate cycle between AMP and adenosine is low (1.9 +/- 0.2 nmol/h per 10(7) cells) in comparison to the rate of AMP deamination.
authors.affiliation: Department of Biochemistry, University of Oxford, U.K.
authors.forename: Z
authors.initials: Z
authors.lastname: Szondy
authors.forename: E A
authors.initials: EA
authors.lastname: Newsholme
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism; D000659:AMP Deaminase / Q000378:metabolism; D000241:Adenosine / Q000378:metabolism*; D058892:Adenosine Deaminase Inhibitors; D000249:Adenosine Monophosphate / Q000378:metabolism*; D000818:Animals; D003208:Concanavalin A; D007700:Kinetics; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D015649:Pentostatin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D058892:Adenosine Deaminase Inhibitors; D003208:Concanavalin A; D015649:Pentostatin; D000249:Adenosine Monophosphate; D015720:5'-Nucleotidase; D000659:AMP Deaminase; D000241:Adenosine