15442-64-5Relevant academic research and scientific papers
Zinc (II) porphyrins as viable scaffolds to stabilize hydrogen sulfide binding at the metal center
Strianese, Maria,Mirra, Silvia,Lamberti, Marina,Pellecchia, Claudio
, p. 426 - 431 (2017)
H2S is an important biological messenger but its reactivity and physiological concentrations are largely controversial. On the other hand, reactivity of H2S with biologically relevant metal scaffolds for the selective tracking of H2S in biological fluids is underexplored. In this work we investigated interaction of monohydrogensulfide with a series of zinc porphyrins by 1H NMR, UV–vis and ESI mass experiments. The results provide evidence that HS? binds the metal center for all the investigated complexes.
Tumor environment-responsive hyaluronan conjugated zinc protoporphyrin for targeted anticancer photodynamic therapy
Gao, Shanghui,Islam, Rayhanul,Fang, Jun
, p. 1 - 15 (2021)
Targeted tumor accumulation, tumor environment responsive drug release, and effective internalization are critical issues being considered in developing anticancer nanomedicine. In this context, we synthesized a tumor environment-responsive nanoprobe for anticancer photodynamic therapy (PDT) that is a hyaluronan conjugated zinc protoporphyrin via an ester bond (HA-es-ZnPP), and we examined its anticancer PDT effect both in vitro and in vivo. HA-es-ZnPP exhibits high water-solubility and forms micelles of ~40 nm in aqueous solutions. HA-es-ZnPP shows fluorescence quenching without apparent1O2 generation under light irradiation because of micelle formation. However,1O2 was extensively generated when the micelle is disrupted, and ZnPP is released. Compared to native ZnPP, HA-es-ZnPP showed lower but comparable intracellular uptake and cytotoxicity in cultured mouse C26 colon cancer cells; more importantly, light irradiation resulted in 10-time increased cytotoxicity, which is the PDT effect. In a mouse sarcoma S180 solid tumor model, HA-es-ZnPP as polymeric micelles exhibited a prolonged systemic circulation time and the consequent tumor-selective accumulation based on the enhanced permeability and retention (EPR) effect was evidenced. Consequently, a remarkable anticancer PDT effect was achieved using HA-es-ZnPP and a xenon light source, without apparent side effects. These findings suggest the potential of HA-es-ZnPP as a candidate anticancer nanomedicine for PDT.
EPR studies of the dynamics of rotation of dioxygen in model cobalt(II) hemes and cobalt-containing hybrid hemoglobins
Bowen, James H.,Shokhirev, Nikolai V.,Raitsimring, Arnold M.,Buttlaire, Daniel H.,Walker, F. Ann
, p. 8683 - 8691 (1997)
Earlier we showed that the shapes of the EPR spectra of cobalt(II) porphyrinate(nitrogen base)(dioxygen) complexes in fluid solution were sensitive to the rate of rotation about the Co-O bond (Walker, F. A.; Bowen, J. H. J. Am. Chem. Soc. 1985, 107, 7632). We have now extended these studies to four metal-substituted hybrid hemoglobins in an attempt to determine whether EPR spectroscopy is sensitive to differences in the mobility of dioxygen in the α and β subunits of the T and R quaternary states. For purposes of this study, [α2(CoO2)β2(FeO2)] and [α2(FeO2)β2(CoO2)] were used as R-state models and [α2(CoO2)β2(Zn)] and [α2(Zn)β2(CoO2)] were used as T-state models. EPR spectra were recorded for samples of each of the above hybrids, equilibrated with 1 atm of O2 gas, as a function of temperature. The progress toward averaging of the EPR signals of the Co-O2-containing subunits was measured as the difference in field positions, ΔH, for the midpoint of the low- and high-field extrema of the derivative EPR spectra. A plot of ΔH vs temperature for each hybrid shows that the [α2(Zn)β2(CoO2)] hybrid is unique in averaging more slowly than the other three (all of which behave similarly), indicating more restricted rotation of dioxygen in T-state β-chain pockets than in the heme distal O2-binding pockets of any other form. This finding is consistent with X-ray crystallographic data which show that valine E11 on the distal side of the T-state β-chain pocket partially blocks the dioxygen binding site (Perutz, M. F.; Fermi, G.; Luisi, B.; Shaanan, B.; Liddington, R. C. Acc. Chem. Res. 1987, 20, 309). Simulation of EPR spectra as a function of jump time provides semiquantitative estimates of the rate of dioxygen rotation in these mixed-metal hemoglobin-dioxygen samples; these rates are in the 1 × 108 s-1 range for three of the hybrids at 35-37°C, and about one-third that value for T-state β(CoO2) centers. These results provide new insight into the highly dynamic nature of dioxygen bound to the metal centers of hemoglobin at physiological temperatures.
Ultrafast dynamics in co-sensitized photocatalysts under visible and NIR light irradiation
Patwari, Jayita,Chatterjee, Arka,Sardar, Samim,Lemmens, Peter,Pal, Samir Kumar
, p. 10418 - 10429 (2018/04/27)
Co-sensitization to achieve a broad absorption window is a widely accepted technique in light harvesting nanohybrid synthesis. Protoporphyrin (PPIX) and squaraine (SQ2) are two organic sensitizers absorbing in the visible and NIR wavelength regions of the solar spectrum, respectively. In the present study, we have sensitized zinc oxide (ZnO) nanoparticles using PPIX and SQ2 simultaneously for their potential use in broad-band solar light harvesting in photocatalysis. F?rster resonance energy transfer (FRET) from PPIX to SQ2 in close proximity to the ZnO surface has been found to enhance visible light photocatalysis. In order to confirm the effect of intermolecular FRET in photocatalysis, the excited state lifetime of the energy donor dye PPIX has been modulated by inserting d10 (ZnII) and d7 (CoII) metal ions in the central position of the dye (PP(Zn) and PP(Co)). In the case of PP(Co)-SQ2, extensive photo-induced ligand to metal charge transfer counteracts the FRET efficiency while efficient FRET has been observed for the PP(Zn)-SQ2 pair. This observation has been justified by the comparison of the visible light photocatalysis of the respective nanohybrids with several control studies. We have also investigated the NIR photocatalysis of the co-sensitized nanohybrids which reveals that reduced aggregation of SQ2 due to co-sensitization of PPIX increases the NIR photocatalysis. However, core-metalation of PPIX reduces the NIR photocatalytic efficacy, most probably due to excited state charge transfer from SQ2 to the metal centre of PP(Co)/PP(Zn) through the conduction band of the host ZnO nanoparticles.
Photosensitized H2 generation from "one-pot" and "two-pot" assemblies of a zinc-porphyrin/platinum nanoparticle/protein scaffold
Clark, Emily R.,Kurtz, Donald M.
, p. 630 - 638 (2016/01/09)
We report photosensitized H2 generation using a protein scaffold that nucleates formation of platinum nanoparticles (Pt NPs) and contains "built-in" photosensitizers. The photosensitizers, zinc-protoporphyrin IX or zinc-mesoporphyrin IX (ZnP) were incorporated in place of the naturally occurring heme in the 24-subunit iron storage protein bacterioferritin (Bfr) when the ZnPs were added to the E. coli expression medium. We engineered a stable dimeric Bfr variant with two protein subunits sandwiching a ZnP. Ten glycines were also substituted in place of residues surrounding the vinyl side of the porphyrin in order increase access of solvent and/or redox agents. An optimized "one-pot" reaction of this glycine-substituted ZnMP-Bfr dimer with a Pt(iv) salt and borohydride resulted in a ～50 : 50 mixture of protein in the form of Pt-free glycine-substituted ZnP-Bfr dimers and re-assembled 24-mers surrounding Pt NPs formed in situ. H2 production occurred upon visible light irradiation of this "one-pot" product when combined with triethanolamine as sacrificial electron donor and methyl viologen as electron relay. An analogous "two-pot" system containing mixtures of separately prepared Pt-free glycine-substituted ZnP-Bfr dimer and porphyrin-free Pt NP@Bfr 24-mer also showed robust photosensitized H2 generation. The glycine-substituted-ZnP-Bfr dimer thus served as photosensitizer for catalytic reduction of methyl viologen by triethanolamine, and the reduced methyl viologen was able to transfer electrons across the Bfr 24-mer protein shell to generate H2 at the enclosed Pt NP in a "dark" reaction. Our results demonstrate that Bfr is a readily manipulatable and versatile scaffold for photosensitized redox chemistry.
Physicochemical properties of protoporphyrin IX by metal ions in acetonitrile-water mixture solution
Bark, Ki-Min,Yang, Jeong-Im,Lee, Ho-Suk,Lee, Jee-Bum,Park, Chul-Ho,Park, Hyoung-Ryun
experimental part, p. 1633 - 1637 (2010/10/20)
The UV-vis absorption spectrum of protoporphyrin IX shows a very sharp and strong absorption maximum peak at 398 nm in acetonitrile-water mixture solution (1:1 v/v). When divalent metal ions such as Cu2+, Zn2+, and Ca2+ ion were added to protoporphyrin IX, metal protoporphyrin IX complexes were thereby produced. Cu-protoporphyrin IX complexes have the largest formation constant (Kf) among them. The fluorescence intensity of protoporphyrin IX was diminished by the presence of Cu2+ , Zn2+ , Ca2+ , Mn2+ , and Ni2+ ions as quenchers. However, Mg2+ , Mn2+ , and Ni 2+ ions are hardly combined with protoporphyrin IX. Mg2+ ion does not take part in the fluorescence quenching process of protoporphyrin IX in acetonitrile-water mixture solution. According to the Stern-Volmer plots, fluorescence quenching by Cu2+ , Zn2+, and Ca2+ ions involves static quenching, which is due to complex formation. On the contrary, dynamic quenching has a large influence on the overall quenching process, when Mn2+ and Ni2+ ions were added to protoporphyrin IX in acetonitrile-water mixture solution.
