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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.


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Journal ArticleDOI
TL;DR: Single turnover experiments with oxygen-loaded HemF under anaerobic conditions demonstrated electron acceptor function for oxygen during the oxidative decarboxylation reaction with the concomitant formation of H2O2.

73 citations

Journal ArticleDOI
TL;DR: It is suggested that SsChlI protein variants containing the substitutions identified in the dominant Oy1 maize alleles lack activity necessary for magnesium chelation and confer a semi-dominant phenotype via competitive inhibition of wild-type Ss chlI.
Abstract: Semi-dominant Oil yellow1 (Oy1) mutants of maize (Zea mays) are deficient in the conversion of protoporphyrin IX to magnesium protoporphyrin IX, the first committed step of chlorophyll biosynthesis. Using a candidate gene approach, a cDNA clone was isolated that was predicted to encode the I subunit of magnesium chelatase (ZmCHLI) and mapped to the same genetic interval as Oy1. Allelic variation was identified at ZmCHLI between wild-type plants and plants carrying semi-dominant alleles of Oy1. These differences revealed putative amino acid substitutions that could account for the alterations in protein function. Candidate lesions were tested by introduction of homologous changes into the Synechocystis magnesium chelatase I gene (SschlI) and characterization of the activity of mutant protein variants in an in vitro enzyme activity assay. The results of these analyses suggest that SsChlI protein variants containing the substitutions identified in the dominant Oy1 maize alleles lack activity necessary for magnesium chelation and confer a semi-dominant phenotype via competitive inhibition of wild-type SsChlI.

73 citations

Journal ArticleDOI
01 Dec 1999-Cancer
TL;DR: The objective of the current study was to examine in vivo the spectral characteristics of red fluorescence emitted from oral carcinomas and to separate the red fluorescent compounds in these lesions by the capillary electrophoretic (CE) method.
Abstract: BACKGROUND Red fluorescence from malignant tumors was observed in experimentally induced rat sarcoma by Policard (1924) and in ulcerated human oral carcinoma by Harris et al. (1987) by examination with ultraviolet (UV) irradiation. The objective of the current study was twofold: to examine in vivo the spectral characteristics of red fluorescence emitted from oral carcinomas and to separate the red fluorescent compounds in these lesions by the capillary electrophoretic (CE) method. METHODS In vivo fluorescence spectral characteristics of oral carcinoma were examined by a near-UV excited autofluorescence diagnosis (NEAD) system developed by the authors. Fluorescence spectra of the extract from carcinomas were measured using a spectrofluorometer. CE was used to separate fluorescent compounds from the oral carcinomas. RESULTS Of the 78 oral carcinomas examined using the NEAD system, 66 carcinomas (85%), including 2 adenoid cystic carcinomas (ACCs) and 14 recurrent squamous cell carcinomas (SCCs), showed porphyrin-like fluorescence spectra. The CE study was performed on three oral SCCs, two of which contained fluorescent compounds other than protoporphyrin IX and zinc protoporphyrin IX, whereas the other SCCs contained the compounds with the same migration time as protoporphyrin IX. CONCLUSIONS Seventy-eight oral carcinomas, including ACCs and recurrent SCCs, were examined using the NEAD system. When exposed to UV light at a wavelength of 410 nm, 85% of the carcinomas showed porphyrin-like fluorescence spectra, whereas the normal mucosa in the oral cavity did not. Porphyrin-like fluorescent compounds were extracted from oral carcinomas and separated by a CE system equipped with a fluorescence detector. The CE data clearly show that compounds vary in each individual carcinoma. Cancer 1999;86:2201–11. © 1999 American Cancer Society.

73 citations

Journal ArticleDOI
TL;DR: ALA may be considered the only current photodynamic therapy (PDT) agent in clinical development that is a biochemical precursor of a photosensitizer.
Abstract: Exogenous provision of 5-aminolevulinic acid (ALA) to many tissues results in the accumulation of sufficient quantities of the endogenous photosensitizer protoporphyrin IX (PpIX) via the heme biosynthetic pathway, to produce a photodynamic effect when exposed to activating light. Therefore, ALA may be considered the only current photodynamic therapy (PDT) agent in clinical development that is a biochemical precursor of a photosensitizer. Topical ALA application, followed by exposure to activating light (ALA PDT), has been reported effective for the treatment of a variety of dermatologic diseases including cutaneous superficial and nodular basal cell carcinoma, Bowen's disease, actinic (solar) keratoses, and T cell lymphoma. Local internal application of ALA has also been used for selective endometrial ablation in animal model systems and, in human clinical studies, it has shown selective formation of PpIX within the endometrium. PpIX induced by ALA application has also been used as a fluorescence detection marker for photodiagnosis (PD) of cancer and dysplastic conditions of the urinary bladder and other organs. Systemic, oral administration of ALA has been used for ALA PDT of superficial head and neck cancer, various gastrointestinal cancers, and the condition known as Barrett's esophagus. This paper reviews the current clinical and development status of ALA PDT and PD.

73 citations

Journal ArticleDOI
TL;DR: The induction of PEPT1 gene and the suppression of ABCG2 gene expression are among the key molecular mechanisms underlying tumor-specific PpIX accumulation after the administration of ALA in bladder cancer.

73 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202383
2022132
202157
202061
201958
201858