title: [Determination of 3,4-dioxyphenyl-L-alanine by spectrophotometric and chromatographic methods in enzymatic synthesis using microbial cells].
abstract: 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.
authors.forename: K I
authors.initials: KI
authors.lastname: Voyvodov
authors.forename: N N
authors.initials: NN
authors.lastname: Zueva
authors.forename: V I
authors.initials: VI
authors.lastname: Iakovleva
mesh_terms: D002396:Catechols; D002851:Chromatography, High Pressure Liquid; D002954:Citrobacter / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000032:analysis* / Q000138:chemical synthesis; D000431:Ethanol; D007202:Indicators and Reagents; D009555:Ninhydrin; D011773:Pyruvates; D019289:Pyruvic Acid; D013056:Spectrophotometry, Ultraviolet; D013057:Spectrum Analysis
chemical_list: D002396:Catechols; D007202:Indicators and Reagents; D011773:Pyruvates; D000431:Ethanol; D004295:Dihydroxyphenylalanine; D019289:Pyruvic Acid; D009555:Ninhydrin; C034221:catechol
vernacular_title: Opredelenie 3,4-dioksifenil-L-alanina spektrofotometricheskim i khromatograficheskim metodami v fermentativnom sinteze s pomoshch'iu kletok mikroorganizmov.