Cationic manganese-porphyrin complexes, free or targetted with an intercalating agent, are able to cleave DNA using oxygen atom donors like potassium monopersulfate or magnesium monoperphthalate as coreactants. Detailed studies of the cleavage of calf thymus DNA, before and after a heating step, show that free bases and 5-methylene-2-furanone are the main reaction products, indicating that hydr...

A simple and efficient protocol is utilized for the transformation studies of a thiophene analog E-resveratrol by photocatalytic oxygenation using an anionic cationic free-base porphyrin, as well their manganese(III) complexes. The starting substrate was chosen representative heterostilbenes with proven good antioxidant activity. experiments were carried out in two photoreactor types (batch mic...

Cytochrome c peroxidase (CCP) is a 32.5 kDa mitochondrial intermembrane space heme peroxidase from Saccharomyces cerevisiae that reduces H(2)O(2) to 2H(2)O by oxidizing two molecules of cytochrome c (cyt c). Here we compare the 1.2 A native structure (CCP) with the 1.3 A structure of its stable oxidized reaction intermediate, Compound I (CCP1). In addition, crystals were analyzed by UV-vis abso...

The development of efficient photo-induced DNA cleavage agents has been of particular interest for biomedical applications such as cancer photodynamic therapy (PDT). Toward this objective, we synthesized a series of cationic bis-porphyrins with various lengths of diamino alkyl linkage, N,N'-bis[4-[10,15,20-tris(1-methylpyridinium-4-yl)porphyrin-5-yl]benzoyl]oligomethylenediamine hexaiodide. The...

Cationic porphyrins are being studied as possible anticancer agents because of their ability to bind to and stabilize DNA guanine quadruplexes (G-quadruplexes). We have shown previously that the cationic porphyrin TMPyP4 is able to bind to and stabilize G-quadruplexes in human telomere sequences, resulting in inhibition of telomerase activity. To better understand the mechanism of action behind...

Two rotaxanes containing zinc porphyrin (ZnP) with crown ether and [60]fullerene (C(60)) with cationic and neutral axles are synthesized. Optimized structures calculated by molecular orbital methods indicate that the rotaxane with an ammonium cation in the center of the axle has a shorter distance between the C(60) and ZnP moieties than that of the rotaxane with a neutral axle because of acylat...