especially AG* for the former case are much smaller than those for Cs+-C221. This could be a result of the larger stability of Cs+-C221 cryptate due to the "cryptate effect". On the other hand, the AS* value for the Cs+-C22 complex is more positive than that for the Cs+-C221 cryptate. We can reasonably assume that this variance is due to the difference between the exchange mechanisms of the cesium ion between the solvated and the complexed sites.
Microbial degradation of halogenated pollutants in wastewaters may be limited by toxic contaminant concentrations or poor membrane permeability of the target compound. Extracellular catalysts can be used in wastewater treatment schemes to overcome these limitations. Water soluble porphyrins with functional groups suitable for immobilization were synthesized as catalysts for reductive dehalogenation of organic contaminants. Synthesized mesosubstituted porphyrins contained (with one exception) three N‐methyl‐4‐pyridinium substituents and a phenyl substituent having the ‐OH, ‐OCH3, ‐NH2, or ‐C(O)OCH2C6H4‐CH=CH2 group located in the p‐position. Catalytic activity was assessed by measuring carbon tetrachloride disappearance in reactions containing a synthetic porphyrin, dithiothreitol, and tris buffer (pH 8.2). Porphyrins metallated with Co or Ni had higher catalytic activities than those metallated with Fe. Changes in meso substituents also altered catalytic activity, with aminophenyl substitution resulting in porphyrins catalyzing the highest rates of carbon tetrachloride disappearance. Although chloroform, dichloromethane, and carbon monoxide were found to be breakdown products, no methane was detected and <40% of the carbon tetrachloride could be recovered in identified volatile products. When 14C carbon tetrachloride was used as substrate, approximately 80% of the label was found in the aqueous phase of the reaction mixture. Synthetic porphyrins have potential utility in wastewater treatment as catalysts for reductive dehalogenation, but further identification of degradative products is necessary.
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A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT
A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT
AbstractRecently cationic porphyrin-peptide conjugates were synthesized to enhance the cellular uptake of porphyrins or deliver the peptide moiety to the close vicinity of nucleic acids. DNA binding of such compounds was not systematically studied yet.We synthesized two new porphyrin-tetrapeptide conjugates which can be considered as a typical monomer unit corresponding to the branches of porphyrin-polymeric branched chain polypeptide conjugates. Tetra-peptides were linked to the tri-cationic meso-tri
A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT
Graphical AbstractResearch Highlights We synthesized two new porphyrin-tetrapeptide conjugates. DNA binding of porphyrin conjugates was studied with spectroscopic methods. Peptide conjugates of cationic porphyrins bind to DNA by two distinct binding modes. Binding modes can be identified as intercalation and external binding.
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