Protoporphyrin IX

About: Protoporphyrin IX is a research topic. Over the lifetime, 2250 publications have been published within this topic receiving 65544 citations. The topic is also known as: PpIX.

Purification and Substrate Specificity of Bovine Liver‐Ferrochelatase

Abstract: Bovine ferrochelatase from liver mitochondria was purified 1434-fold with a 31% yield to apparent homogeneity by a procedure involving solubilization, ammonium sulfate fractionation and blue Sepharose CL-6B chromatography. The molecular weight of the homogeneous protein was 42 500 when measured by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. A molecular weight of approximately 200 000 was obtained by Sepharose 6B gel filtration. The specific activity for mesoheme synthesis was 413 nmol x mg protein-1 x min-1 at 37 degrees C and for protoheme synthesis 88 nmol x mg-1 x min-1. The optimum pH was 8.0 and Km values for the substrates were: protoporphyrin IX, 54 microM; mesoporphyrin IX, 46 microM; iron with protoporphyrin IX, 46 microM, iron with mesoporphyrin IX, 44 microM. The purified enzyme inserted iron into the following dicarboxylic porphyrins in descending order: meso-, deutero-, 2,4-diacetyldeutero-, hemato-, and protoporphyrin IX. This did not take place in the case of 2,4-diformyldeuteroporphyrin IX. Porphyrin c was converted to only a negligible amount of heme c, and coproporphyrin III did not act as a substrate at all. When metal specificity was examined, the highest value was obtained with zinc, decreasing in order with iron, cobalt and nickel. The enzyme failed to catalyze the insertion of copper or manganese into porphyrin. An antibody specific for the purified bovine ferrochelatase was prepared, and studies confirmed that the synthetic activities of iron-porphyrin, zinc-porphyrin and cobalt-porphyrin are ascribable to ferrochelatase.

Fluorescence induction of protoporphyrin IX by a new 5-aminolevulinic acid nanoemulsion used for photodynamic therapy in a full-thickness ex vivo skin model.

Abstract: An ex vivo porcine skin model was utilized to analyse the penetration of 5-aminolevulinic acid (5-ALA) contained in a nanoemulsion-based formulation BF-200 ALA (10% 5-ALA-hydrochloride) versus 16% aminolevulinate methyl ester-hydrochloride in a commercially cream (MAL cream) by fluorescence microscopy of their common metabolite protoporphyrin IX (PpIX) after 3, 5, 8 and 12 h. Fluorescence signals of PpIX in pig skin treated with BF-200 ALA were stronger than those for MAL cream. At 8 and 12 h, the PpIX fluorescence signals were 4.8- and 5.0-fold higher than those measured after MAL cream application. Fluorescence signals of PpIX after application of BF-200 ALA were detected in deeper tissue layers of the epidermis than after application of MAL cream (97.2 +/- 5.7 microm for BF-200 ALA vs 42.0 +/- 4.2 microm for MAL cream). These data implicate that BF-200 ALA in photodynamic therapy might lead to a superior therapeutically effect of intraepidermal (in situ) squamous cell carcinomas.

Protoporphyrin IX and oxidative stress.

Abstract: The short- and long-term pro-oxidant effect of protoporphyrin IX (PROTO) administration to mice was studied in liver. A peak of liver porphyrin accumulation was found 2 h after the injection of PROTO (3.5 mg/kg, i.p.); then the amount of porphyrins diminished due to biliar excretion. After several doses of PROTO (1 dose every 24 h up to 5 doses) a sustained enhancement of liver porphyrins was observed. The activity of δ-amino-levulinic acid synthetase was induced 70–90% over the control values 4 h after the first injection of PROTO and stayed at these high levels throughout the period of the assay. Administration of PROTO induced rapid liver damage, involving lipid peroxidation. Hepatic GSH content was increased 2 h after the first injection of PROTO, but then decreased below the control values which were maintained after several doses of porphyrin. After a single dose of PROTO, Cu-Zn superoxide dismutase (SOD) was rapidly induced, suggesting that superoxide radicals had been generated. Increased levels o...

Photodestruction of tumor cells by induction of endogenous accumulation of protoporphyrin IX: enhancement by 1,10-phenanthroline.

Abstract: Rapidly proliferating transformed mammalian cells can be photodestroyed in vitro upon inducing the accumulation of endogenous protoporphyrin IX (Proto). Proto biosynthesis and accumulation were triggered by manipulation of the porphyrin-heme biosynthetic pathway. Proto accumulation in cultured cells was induced by treatment with 1.0 mM delta-aminolevulinic acid (ALA), a naturally occurring 5-carbon amino acid, for 3.5 h. In darkness, significant Proto accumulation became evident within 3.5 h of incubation. In the light, the accumulated tetrapyrroles triggered destruction of treated cells within the first 30 min of illumination, probably via the rapid oxidation of cellular constituents by singlet oxygen. Protoporphyrin IX accumulation and specific cell lysis increased significantly by inclusion of 0.75 mM 1,10-phenanthroline (Oph), a tetrapyrrole biosynthesis modulator. Slower growing untransformed cells did not accumulate significant amounts of Proto following ALA and Oph treatment unless stimulated to proliferate with the mitogenic lectin Concanavalin A.