Method and composition for the enzymic determination of aspartame
AssigneeMerck Patent GmbH
InventorReiner Gromes
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Abstract
The invention relates to a method and a composition for the enzymic determination of aspartame in aqueous solutions. The method is carried out such that the sample solution is incubated essentially in the presence of oxo-glutarate, glutamate-oxaloacetate transaminase (GOT), malate dehydrogenase (MDH), NADH and a protease, and the decrease in the NADH extinction is measured photometrically.
Claims9
A method for the enzymic determination of aspartame in an aqueous sample solution, consisting essentially of
- incubating the sample solution in the presence of a protease which hydrolyzes aspartame to aspartic acid and phenylalanine methyl ester, and the aspartic acid detection reagents oxoglutarate, glutamate-oxaloacetate transaminase (GOT), malate dehydrogenase (MDH) and nicotinamide adenine dinucleotide (reduced) (NADH), and, optionally, pyridoxal 5-phosphate,
- measuring the decrease in the NADH extinction photometrically, and
- determining the amount of aspartame in the sample solution by comparison with the decrease in NADH extinction in a standard solution of a known amount of aspartame;
- whereby the determination can be carried out in the presence of all the reagents in a single reaction vessel.
A method for the enzymic determination of aspartame in an aqueous sample solution, consisting essentially of
- incubating sample solution with the aspartic acid detection reagents oxoglutarate, glutamate-oxaloacetate transaminase (GOT), malate dehydrogenase (MDH) and nicotinamide adenine dinucleotide (reduced) (NADH), and, optionally, pyridoxal 5-phosphate,
- measuring the E.sub.1 NADH extinction photometrically,
- adding a protease which hydrolyzes aspartame to aspartic acid and phenylalanine methyl ester to the sample solution containing said aspartic acid detection reagents, and further incubating the sample solution,
- measuring the decrease in the NADH extinction photometrically, and
- determining the amount of aspartame in the sample solution by comparison with the decrease in NADH extinction in a standard solution of a known amount of aspartame;
- whereby the determination can be carried out in the presence of all the reagents in a single reaction vessel.
A composition for the enzymic determination of aspartame in aqueous solutions, consisting essentially of effective amounts of oxoglutarate, GOT, MDH, NADH and a protease, and, optionally, pyridoxal 5-phosphate.
Dependencies are inferred from the claim text.