Biomaterial Database

A continuous spectrophotometric method based on enzymatic cycling for determining L-glutamate. 1998

E Valero, and F Garcia-Carmona

E. U. Politécnica de Albacete, Universidad de Castilla-La Mancha, Albacete, E-02071, Spain.

A continuous spectrophotometric assay for determining low levels of L-glutamate is described. The assay, which involves the enzymes L-glutamate oxidase and glutamic-pyruvic transaminase, is based on the recycling of L-glutamate into alpha-ketoglutarate, with the concomitant appearance of one molecule of hydrogen peroxide in each turn of the cycle. This is subsequently reduced by means of a peroxidase-coupled reaction, using 2, 2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) as substrate. In this way the interference observed in the cyclic assay using glutamic-oxalacetic transaminase, which is due to the fact that L-aspartate is also a substrate of L-glutamate oxidase, is eliminated. A kinetic study of the system is presented, with the accumulation of chromophore being seen to undergo a transient phase, which is dependent both on the cycling rate and on the auxiliary enzyme concentration. The kinetic parameters characterizing the system have been determined, making it possible to optimize costs with respect to the enzymes involved in the cycle, since the minimum amount needed for a given rate constant of the cycle can be calculated.

UI	MeSH Term	Description	Entries
D007202	Indicators and Reagents	Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)	Indicator,Reagent,Reagents,Indicators,Reagents and Indicators
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D003365	Costs and Cost Analysis	Absolute, comparative, or differential costs pertaining to services, institutions, resources, etc., or the analysis and study of these costs.	Affordability,Analysis, Cost,Cost,Cost Analysis,Cost Comparison,Cost Measures,Cost-Minimization Analysis,Costs and Cost Analyses,Costs, Cost Analysis,Pricing,Affordabilities,Analyses, Cost,Analyses, Cost-Minimization,Analysis, Cost-Minimization,Comparison, Cost,Comparisons, Cost,Cost Analyses,Cost Comparisons,Cost Measure,Cost Minimization Analysis,Cost, Cost Analysis,Cost-Minimization Analyses,Costs,Measure, Cost,Measures, Cost
D000594	Amino Acid Oxidoreductases	A class of enzymes that catalyze oxidation-reduction reactions of amino acids.	Acid Oxidoreductases, Amino,Oxidoreductases, Amino Acid
D001219	Aspartate Aminotransferases	Enzymes of the transferase class that catalyze the conversion of L-aspartate and 2-ketoglutarate to oxaloacetate and L-glutamate. EC 2.6.1.1.	Aspartate Aminotransferase,Aspartate Transaminase,Glutamic-Oxaloacetic Transaminase,SGOT,Aspartate Apoaminotransferase,Glutamate-Aspartate Transaminase,L-Aspartate-2-Oxoglutarate Aminotransferase,Serum Glutamic-Oxaloacetic Transaminase,Aminotransferase, Aspartate,Aminotransferase, L-Aspartate-2-Oxoglutarate,Aminotransferases, Aspartate,Apoaminotransferase, Aspartate,Glutamate Aspartate Transaminase,Glutamic Oxaloacetic Transaminase,Glutamic-Oxaloacetic Transaminase, Serum,L Aspartate 2 Oxoglutarate Aminotransferase,Serum Glutamic Oxaloacetic Transaminase,Transaminase, Aspartate,Transaminase, Glutamate-Aspartate,Transaminase, Glutamic-Oxaloacetic,Transaminase, Serum Glutamic-Oxaloacetic
D013057	Spectrum Analysis	The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Spectroscopy,Analysis, Spectrum,Spectrometry
D013451	Sulfonic Acids	Inorganic or organic oxy acids of sulfur which contain the RSO2(OH) radical.	Sulfonic Acid,Acid, Sulfonic,Acids, Sulfonic
D052160	Benzothiazoles	Compounds with a benzene ring fused to a thiazole ring.
D018698	Glutamic Acid	A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.	Aluminum L-Glutamate,Glutamate,Potassium Glutamate,D-Glutamate,Glutamic Acid, (D)-Isomer,L-Glutamate,L-Glutamic Acid,Aluminum L Glutamate,D Glutamate,Glutamate, Potassium,L Glutamate,L Glutamic Acid,L-Glutamate, Aluminum