Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.1 (asparaginase)
 2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The analytical methodologies for the determination of free amino acids in plasma, serum, erythrocytes and leukemic cells are described. Deproteinization of the sample by methanol or organic acids is followed by derivatization with phenylisothiocyanate to form stable phenylthiocarbamylamino acid derivatives. The derivatives are separated by reversed-phase high-performance liquid chromatography in 80 min using a 5-microns C18 column (250 X 4 mm I.D.) and monitored by ultraviolet detection at 254 nm. Twenty physiological amino acids are resolved and quantified in plasma and erythrocyte samples. The resolution and sensitivity of the analytical method permitted unequivocal quantification of very low asparagine and glutamine levels in leukemic cells and growth media following treatment with asparaginase and glutaminase enzymes despite the presence of high aspartic and glutamic acid levels.
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PMID:Sensitive analysis of asparagine and glutamine in physiological fluids and cells by precolumn derivatization with phenylisothiocyanate and reversed-phase high-performance liquid chromatography. 371 Dec 4

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.
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PMID:Determination of L-asparagine in biological samples in the presence of L-asparaginase. 795 83