care is taken to inhibit ex vivo enzyme activity.4 We sent a blinded set of our samples to Dr Asselin, and she confirmed the asparagine values we reported. Liver perfusion studies and modeling of asparaginase treatment suggest that there is a high rate of asparagine input into the circulation from diet and the tissues.5,6 An equilibrium between the rate of asparagine input and the asparaginase ...

care is taken to inhibit ex vivo enzyme activity.4 We sent a blinded set of our samples to Dr Asselin, and she confirmed the asparagine values we reported. Liver perfusion studies and modeling of asparaginase treatment suggest that there is a high rate of asparagine input into the circulation from diet and the tissues.5,6 An equilibrium between the rate of asparagine input and the asparaginase ...

Introduction Bacterial asparaginase obtained from Escherichia coli and Erwinia chrysanthemi are used as medicine to treat acute lymphocytic leukemia and non-Hodgkin lymphoma. Despite the therapeutic properties of such enzymes there have been reports on adverse reactions, eventually so severe as to impede some patients of using the medicine. Besides, the only drug Brazil used to import is no lon...

In the present study, Streptomyces gulbargensis and its mutant form, S.gulbargensis mu24, immobilized on polyurethane foam were investigated for the production of L-asparaginase using groundnut cake extract as medium. The medium with an initial pH of 8.5 was inoculated with free and immobilized cells separately and then subjected to fermentation by incubation at 40oC and shaking at 200 rev/min....

The cooperation between bone marrow and thymus cells in restoring the hemolytic antibody response to sheep erythrocytes in immunosuppressed recipients was markedly inhibited when donor mice were treated with L-asparaginase, a known inhibitor of lymphocyte function. The marrow cell population was shown to be a major target for the immunosuppressive activity of asparaginase, since thymus cells fr...

Polyethylene glycol (PEG) conjugation technology has been successfully applied to improve the performance of protein drugs. In this study, L-asparaginase was N-terminal site-specifically modified by alkylating PEG with monomethoxy polyethylene glycol-propionaldehyde (mPEG-ALD20000). The optimum reaction parameters were determined as pH 5.0, a molar ratio of mPEG-ALD2000 to L-asparaginase of 10:...

Acinetobacter glutaminase-asparaginase (AGA) and Escherichia coli asparaginase were compared for their effects on plasma and tissue levels of amino acids, ammonia, and glutamyl transferase activity in the mouse. Free asparagine was depleted similarly in plasma and tissues by both enzymes. AGA treatment produced partial depletion of glutamine concentrations in muscle, spleen, small intestine, an...

In vivo metabolism of lysine and arginine is markedly inhibited (p < 0.025) in P1798 lymphosarcoma within 1 hr after intraperitoneal injection of 1 unit of Escherichia coli L-asparaginase II. Two hr after treatment, there is substan tial inhibition of thymidine transport but no effect on incorporation of thymidine. None of these effects were observed in the L-asparaginase-resistant subline of t...

Acinetobacier glutaminase-asparaginase (AGA) and Escherichia coli asparaginase were compared for their effects on plasma and tissue levels of amino acids, am monia, and glutamyl transferase activity in the mouse. Free asparagine was depleted similarly in plasma and tissues by both enzymes. AGA treatment produced partial depletion of glutamine concentrations in muscle, spleen, small intes tine, ...

L-asparaginase administered in therapeutic doses to mice was found to reduce the total number of nucleated marrow cells and colony-forming cells when assayed 4 hours after administration by a methylcellulose bone marrow culture technique. Both marrow cellularity and the fraction of surviving IVCFC/femur were normal by 24 hours after injection, except with very large doses, at a time when there ...