Concentrations Of L-asparagine Research Articles

Reagentless determination of L-asparagine and L-arginine via the combined use of immobilized enzymes and an ion-selective electrode.

New methods for the determination of L-asparagine and arginine are described. Solutions containing L-asparagine were pumped through an asparaginase tube, which catalyzed the hydrolysis of L-asparagine to L-aspartis acid and ammonium ion. For L-arginine determination, solutions containing L-arginine were pumped through an arginase-urease tube. This dual enzyme tube catalyzed the conversion of L-arginine to L-ornithine, carbon dioxide, and ammonium ion. The ammonium ion concentrations in the effluent of the enzyme tubes were determined quantitatively by an ammounin-ion-selective electrode. The potentiometric response of the electrode was directly proportional to the logarithm of the concentration of L-asparagine and L-arginine in the range of 0.1-50 mM. An equation relating the electrode response and the substrate concentration is derived.

Determination of l-asparagine and l-arginine with open tube enzyme reactors

1. 1. Solutions containing L-asparagine or L-arginine were pumped through open tube enzyme reactors, the reactors catalyze the convertion of l-asparagine or l-arginine to ammonia, the ammonia concentration in the effluent was determined and found to be directly proportional to the concentration of l-asparagine or l-arginine in the range 3–25 mM and 1–12 mM, respectively. 2. 2. The reactor for l-asparagine determination was prepared by immobilizing asparaginase on the interior surface of a nylon tubing. 3. 3. The reactor for l-arginine determination was prepared by simultaneous immobilization of arginase and urease, this dual enzyme reactor catalyzes two consecutive reactions leading to the formation of ammonia from l-arginine.

A spectrophotometric method for the simultaneous measurement of l-glutamine and l-asparagine in biological materials

A rapid and specific spectrophotometric method for measuring the concentration of l-asparagine and l-glutamine in biological materials is presented. Ammonia, released by the enzymic hydrolysis of l-asparagine and l-glutamine, is measured with l-glutamic dehydrogenase. l-Asparaginase from Escherichia coli is used to deaminate first l-asparagine and then l-glutamine. The applicability of the method to biological materials has been demonstrated using extracts of the livers and brains of mice treated with the convulsant amino acid analog, l-methionine- dl-sulfoximine. In animals given this agent subacutely, the concentration of l-glutamine in brain and liver fell significantly, whereas l-asparagine was unaffected. Since even fresh plasma may be used, the assay promises to be a value in measuring the depletion of l-asparagine and l-glutamine in the plasma of patients receiving the oncolytic enzyme, l-asparaginase.

Nutritional Physiology.

SUMMARY Nutritional physiology of two isolates of Trichothecium roseum was investigated. Optimum temperature and pH for both the isolates were 28 C and 6.0, respectively. D-glucose was the the best substrate for both isolates. There was an increase in mycelial growth as the concentration of D-glucose was increased from 2.5 to 20 g/liter. The amount of growth varied with the nitrogen source, the best growth of the isolate from Mains was on L-asparagine and that of the isolate from Prunus on L-glutamic acid. There was an increase in mycelial growth as the concentration of L-asparagine was increased. There appeared to be no correlation between mycelial growth and the rate of assimilation of amino acid. The presence or absence of amino acids had no correlation with presence or absence of glucose in the medium. The best C/N concentration for maximum growth (D-glucose: L-asparagine) was found to be 30:10.4 g/liter. Pink rot of apple caused by Trichothecium roseum (Pers.) Link ex