title: o-Phthaldialdehyde derivatization of histidine: stoichiometry, stability and reaction mechanism.
abstract: The irregular behavior of histidine in its reaction with the o-phthaldialdehyde (OPA) reagents has been studied. Histidine provides more than one OPA derivative. Similarly to all those primary amino group-containing compounds that do have in their initial structure the -CH2-NH2 moiety. The ratio of histidine's initially formed and transformed OPA derivatives depends on the temperature: very likely due to the fact that elevated temperature favors the intra-molecular rearrangement of histidine resulting in the formation of the -CH2-NH2 moiety-containing tautomer(s). The higher the temperature the higher the amount of the transformed species. The composition of the initially and transformed OPA derivatives of histidine were identified on the basis of their on-line HPLC-electrospray ionization (ESI) MS spectra and computations. The initially formed species has been identified as the classical isoindole, while the transformed one contains an additional OPA molecule.
authors.affiliation: Institute of Inorganic and Analytical Chemistry, L. Eötvös University, P.O. Box 32, H-1518 Budapest 112, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Csámpai
authors.forename: D
authors.initials: D
authors.lastname: Kutlán
authors.forename: F
authors.initials: F
authors.lastname: Tóth
authors.forename: I
authors.initials: I
authors.lastname: Molnár-Perl
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D002021:Buffers; D002851:Chromatography, High Pressure Liquid; D006639:Histidine / Q000031:analogs & derivatives* / Q000737:chemistry*; D007202:Indicators and Reagents; D012996:Solutions; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D009764:o-Phthalaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D002021:Buffers; D007202:Indicators and Reagents; D012996:Solutions; D006639:Histidine; D009764:o-Phthalaldehyde