title: [Nonenzymatic covalent modification of human hemoglobin by pyridoxal-5-phosphate under the effect of visible light].
abstract: Under the action of visible light, PLP with apo-, oxy- and deoxy-Hb at 4-20 degrees C and neutral pH produced adducts stable to dialysis and Sephadex gel filtration. The stable adduct formation enhanced with an increase in radiation intensity and/or irradiation time. Under light, production of stable adducts occurred most effectively for apo-Hb and was significantly slowed down in the case of met-Hb as well as in the presence of an electron acceptor, methylene blue. PLP-Hb adducts possessed intense fluorescence coinciding in properties with the fluorescence of stable PLP adducts obtained after Schiff base reduction by NaBH4. Stable adduct formation is assumed to proceed owing to Schiff base aldimin link reduction by photoejected electrons. During isoelectrofocusing of hemoglobins which had formed stable adducts with PLP under light or after NaBH4 treatment of solutions, essentially the same pictures were observed as to the number of new bands and their position in the isoelectroforegram, with the band intensity being different. This is related to the distinctions in the electron seeking properties of the Schiff bases produced by PLP with alpha-NH2 groups of Val-1 and epsilon-NH2 groups of lysine residues of the protein alpha- and beta-chains.
authors.forename: I I
authors.initials: II
authors.lastname: Stepuro
authors.forename: N V
authors.initials: NV
authors.lastname: Konovalova
authors.forename: A A
authors.initials: AA
authors.lastname: Solodunov
authors.forename: A S
authors.initials: AS
authors.lastname: Tyshchenko
mesh_terms: D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D006454:Hemoglobins / Q000737:chemistry* / Q000528:radiation effects; D006801:Humans; D007525:Isoelectric Focusing; D008027:Light; D011732:Pyridoxal Phosphate / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D006454:Hemoglobins; D012545:Schiff Bases; D011732:Pyridoxal Phosphate
vernacular_title: Neénzimaticheskaia kovalentnaia modifikatsiia gemoblobina cheloveka piridoksal'-5-fosfatom pod deĭstviem vidimogo sveta.