title: Interactions of zinc octacarboxyphthalocyanine with selected amino acids and with albumin.
abstract: Effect of selected amino acids (glycine, l-histidine, l-cysteine, l-serine, l-tryptophan) and albumin on the spectroscopic properties and photostability of zinc octacarboxyphthalocyanine (ZnPcOC) was explored in the phosphate buffer at a pH of 7.0. The photodegradation of ZnPcOC alone and in the presence of amino acids or albumin has been investigated in aqueous phase using UV-366nm and daylight irradiation. Kinetic analysis showed that the interaction with amino acids or albumin enhances the photostability of ZnPcOC. To answer the question of how zinc phthalocyanine interacts with amino acids extensive DFT calculations were performed. Analysis of the optimized geometry features of ZnPcOC: amino acids complexes in the gas phase and in water environment as well as the BSSE corrected interaction energies indicates that the more likely is the formation of equatorial complexes in which H-bonds are formed between the COOH groups of the phthalocyanine and carboxyl or amino groups of amino acids. UV-Vis spectra calculated by employing time dependent density functional theory (TD-DFT) are also consistent with this conclusion.
authors.affiliation: Department of Physical Chemistry and Molecular Modeling, Faculty of Chemistry, University of Opole, Oleska 48, Opole 45-052, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Kliber
authors.affiliation: Department of Physical Chemistry and Molecular Modeling, Faculty of Chemistry, University of Opole, Oleska 48, Opole 45-052, Poland.
authors.forename: Małgorzata A
authors.initials: MA
authors.lastname: Broda
authors.affiliation: Department of Physical Chemistry and Molecular Modeling, Faculty of Chemistry, University of Opole, Oleska 48, Opole 45-052, Poland. Electronic address: joanna.nackiewicz@uni.opole.pl.
authors.forename: Joanna
authors.initials: J
authors.lastname: Nackiewicz
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D019281:Dimerization; D007211:Indoles / Q000737:chemistry / Q000378:metabolism*; D054833:Isoindoles; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry / Q000378:metabolism*; D010782:Photolysis; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D014466:Ultraviolet Rays; D017967:Zinc Compounds
chemical_list: D000596:Amino Acids; D007211:Indoles; D054833:Isoindoles; D009942:Organometallic Compounds; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D012710:Serum Albumin, Bovine
keywords: Amino acid; Photodynamic therapy; Protein; Theoretical calculations; UV–Vis spectra; Zinc octacarboxyphthalocyanine