N6-methyladenine (6-methylaminopurine [6-MA]), a plant growth regulator and a normal constituent of nucleic acids, has been found to inhibit the growth of Trypanosoma cruzi, Leishmania braziliensis, L. donovani, L. tarentolae, L. mexicana, and Crithidia fasciculata. The extent of growth inhibition in these organisms is related to the sensitivity of guanine deaminase (guanine aminohydrolase, EC ...

Patients with acute intermittent porphyria can be subdivided into three groups, according to the porphobilinogen deaminase activity in their erythrocytes. The first group has lowered, the second overlapping and the third normal porphobilinogen deaminase activity. Of 385 acute intermittent porphyria patients 5% had normal porphobilinogen deaminase activity. Gene carriers of acute intermittent po...

Recent advances in the application of kinetic isotope effects to enzyme-catalyzed reactions have provided reliable information for enzymatic transition state structures. A method is presented for quantifying the similarity of substrates and inhibitors with their enzyme-stabilized transition states. On the basis of transition-state stabilization theory for enzymatic reactions, molecules most sim...

Purine nucleotide catabolism is common to most organisms and involves a guanine deaminase to convert guanine to xanthine in animals, invertebrates, and microorganisms. Using metabolomic analysis of mutants, we demonstrate that Arabidopsis thaliana uses an alternative catabolic route employing a highly specific guanosine deaminase (GSDA) not reported from any organism so far. The enzyme is ubiqu...

This study examined the hypothesis that increases in myocardial blood flow during exercise are mediated by adenosine-induced coronary vasodilation. Active hyperemia associated with graded treadmill exercise and coronary reactive hyperemia were examined in chronically instrumented awake dogs during control conditions, after intracoronary infusion of adenosine deaminase (5 units/kg/min for 10 min...

Cultured leukemic T-lymphoblasts, incubated in the presence of inhibitors of adenosine deaminase, are exquisitely sensitive to growth inhibition by deoxyadenosine. An analogy between this phenomenon and human combined immunodeficiency disease associated with inborn adenosine deaminase deficiency and the use of inhibitors of adenosine deaminase in the management of T-cell acute lymphoblastic leu...

Adenosine deaminase (ADA) can aid in the diagnosis of tuberculous pleural effusions, but false-positive findings from lymphocytic effusions have been reported. The purpose of this study is to assess the ADA levels in nontuberculous lymphocytic pleural effusions (lymphocyte count > 50%) of different aetiologies. Altogether, 410 nontuberculous lymphocytic pleural fluid samples were consecutively ...

plant growth-promoting rhizobacteria (pgpr) is an alternative to chemical pesticides against harmful microorganisms especially soil-borne diseases. rhizoctonia solani is one of the most important soil-borne fungal pathogens that causes serious damages to important crops. in this study, to screen successful pseudomonas bacterial isolates, the inhibition of pathogen growth was evaluated in-vitro....

Adenylate deaminase (EC 3.5.4.6) may help to regulate the adenine nucleotide catabolism characteristic of such disease states as myocardial ischaemia. We report analysis of the molecular, kinetic and allosteric properties of rabbit heart adenylate deaminase when extracted and purified under phosphate-free conditions (i.e., with Hepes/KOH). The enzyme's subunit molecular mass (approximately 81 k...

6-Methoxypurine arabinoside (ara-M) exhibits potent activity against varicella-zoster virus (VZV) as a result of ara-M's anabolism to the triphosphate of adenine arabinoside (ara-ATP) in VZV-infected cells. The adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) enhanced the formation of ara-ATP by inhibiting ara-M demethoxylation. In contrast, deoxycoformycin and coformyc...