High concentrations of adenosine are known to be toxic to fibroblasts and lymphocytes under conditions of in vitro culture (1,2). Normally, accumulation of adenosine nucleotides in all mammalian cells is prevented by the presence of adenosine deaminase, an aminohydrolase which converts adenosine to inosine (3). A genetically determined deficiency of adenosine deaminase has been associated with ...

A novel fusion gene has been created in which the expression of a dominant selectable marker, the human multidrug resistance gene, is directly linked to the expression of human adenosine deaminase cDNA. The chimeric gene was inserted between the long terminal repeats of a Harvey murine sarcoma virus expression vector and used to transfect drug-sensitive human KB carcinoma cells. Transfectants w...

Adechlorin exhibiting a potent inhibitory activity against calf intestinal adenosine deaminase was isolated from the cultured broth of Actinomadura sp. OMR-37. The molecular formula was C11H15N4O4Cl. The aglycone of adechlorin was identical with that of the known adenosine deaminase inhibitors coformycin and 2'-deoxycoformycin. Adechlorin did not exhibit inhibitory activity against various bact...

Isocoformycin is a structural isomer of coformycin which has been demonstrated to be a potent inhibitor of adenosine deaminase. Isocoformycin showed a weaker inhibition of this enzyme than coformycin; the binding of coformycin to enzyme was irreversible, but isocoformycin inhibition was competitive with substrate. The Ki value of isocoformycin was 4.5 approximately 10 X 10(-8) M. Following intr...

The purpose of this report is to compare measurements of enzymatic activities and cell surface markers as methods of distinguishing subtypes of lymphoid leukemias of childhood. Twenty-six children ages 2-15 yr were studied. Terminal deoxynucleotidyl transferase (TdT) activity was high in blasts from all 20 children with either null or T cell acute lymphoblastic leukemia. The activity of adenosi...

Adenosine deaminase (Enzymes Commission No 3.5.4.4) is an enzyme capable of catalysing the catabolism of purine bases. Previous studies have shown that this enzyme may be useful in recognition of a tuberculous aetiology of pleural, peritoneal, or meningeal effusions.-̀ s Adenosine deaminase assay is a simple, sensitive, and specific diagnostic procedure in these conditions but its use in diagnos...

1. The maximal activities of 5'-nucleotidase, adenosine kinase and adenosine deaminase together with the Km values for their respective substrates were measured in muscle, nervous tissue and liver from a large range of animals to provide information on the mechanism of control of adenosine concentration in the tissues. 2. Detailed evidence that the methods used were optimal for the extraction a...

The role of enzymatic deamination of adenosine monophosphate (AMP) and adenosine in the in vitro growth of the malaria parasite Plasmodium falciparum was investigated by means of human red cells deficient in AMP deaminase to which the adenosine deaminase inhibitor 2'-deoxycoformycin was added. Malaria parasites grew normally in red cells lacking one or both of these enzyme activities. As a furt...