Determination of L-asparagine in biological samples in the presence of L-asparaginase.
The antileukaemic efficacy of L-asparaginase is related to the ability of the enzyme to induce the complete disappearance from plasma of L-asparagine, an amino acid essential to lymphoblastic leukaemia cells. It is not feasible to monitor L-asparagine plasma levels in patients under L-asparaginase treatment using the usual analytical procedures as the enzyme continues the hydrolysis of L-asparagine after blood sampling and during plasma extraction. A method was therefore developed for the determination of L-asparagine in patients receiving L-asparaginase. Sulphosalicylic acid is added to blood samples to deproteinize and inactivate L-asparaginase rapidly. The samples are then analysed by HPLC using a Novapack C18 column and fluorescence detection. With the same method L-asparagine is determined in blood cells and, by difference, plasma levels are calculated. This method is highly specific and sufficiently simple and sensitive for clinical use.
Mario Negri Institute, Milan, Italy.
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D001215:Asparaginase / Q000037:antagonists & inhibitors / Q000627:therapeutic use*; D001216:Asparagine / Q000097:blood*; D001557:Benzenesulfonates; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000706:statistics & numerical data; D004355:Drug Stability; D004885:Erwinia / Q000201:enzymology; D004912:Erythrocytes / Q000737:chemistry; D005615:Freezing; D006801:Humans; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood* / Q000188:drug therapy; D011786:Quality Control; D012459:Salicylates / Q000494:pharmacology; D012680:Sensitivity and Specificity
D001557:Benzenesulfonates; D012459:Salicylates; D001216:Asparagine; D001215:Asparaginase; C003366:sulfosalicylic acid