Determination of 3,4-dioxyphenyl-L-alanine by spectrophotometric and chromatographic methods in enzymatic synthesis using microbial cells

A possibility of using the ninhydrin reaction for 3,4-dihydroxyphenyl-L-alanine (DOPA) determining during the synthesis from pyrocatechol and ammonium pyruvate was verified by using free and immobilized cells of Citrobacter freundii, st. 62. Spectrophotometric assay was performed at the adsorption m...

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Bibliographic Details
Published in:	Prikladnaja biohimija i mikrobiologija Vol. 25; no. 2; p. 278
Main Authors:	Voyvodov, K I, Zueva, N N, Iakovleva, V I
Format:	Journal Article
Language:	Russian
Published:	Russia (Federation) 01-03-1989
Subjects:	Catechols Chromatography, High Pressure Liquid Citrobacter - metabolism Dihydroxyphenylalanine - analysis Dihydroxyphenylalanine - chemical synthesis Ethanol Indicators and Reagents Ninhydrin Pyruvates Pyruvic Acid Spectrophotometry, Ultraviolet Spectrum Analysis
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Summary:	A possibility of using the ninhydrin reaction for 3,4-dihydroxyphenyl-L-alanine (DOPA) determining during the synthesis from pyrocatechol and ammonium pyruvate was verified by using free and immobilized cells of Citrobacter freundii, st. 62. Spectrophotometric assay was performed at the adsorption maximum for the DOPA-ninhydrin complex at 390 nm. DOPA can be reliably quantified in the presence of all components at 20-fold and greater dilution of the reaction mixture. A high-sensitive quantitative assay of the reaction mixture was developed based on phase-reversed HPLC. A quantitative correlation was observed between spectrophotometric and chromatographic assays. The assays were employed to study in detail the initial period and equilibrium of DOPA synthesis and its characteristic features, which made it possible to construct a kinetic model of the process.
ISSN:	0555-1099