title: Reagentless determination of L-asparagine and L-arginine via the combined use of immobilized enzymes and an ion-selective electrode.
abstract: 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.
mesh_terms: D001119:Arginase; D001120:Arginine / Q000032:analysis*; D001215:Asparaginase; D001216:Asparagine / Q000032:analysis*; D004566:Electrodes; D008433:Mathematics; D008722:Methods; D011485:Protein Binding
chemical_list: D001216:Asparagine; D001120:Arginine; D001215:Asparaginase; D001119:Arginase