Topic
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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TL;DR: In vivo and in vitro, the conjugation of ALA to a second-generation dxcendrimer for enhancing porphyrin synthesis in vitro and in vivo in a murine tumour model using systemic i.p. administration of 5-aminolaevulinic acid (ALA) showed good correlation with higher cellular ALA dendrimer accumulation.
57 citations
TL;DR: It is concluded that in FLCs, hemin induces ferritin H-chain biosynthesis by multiple mechanisms: a transcriptional mechanism exerted also by protoporphyrin IX and a translational one, not displayed by protomolecularin IX but shared with FAC.
Abstract: The mechanisms that regulate the expression of the H chain of the iron storage protein ferritin in Friend erythroleukemia cells (FLCs) after exposure to hemin (ferric protoporphyrin IX), protoporphyrin IX, and ferric ammonium citrate (FAC) have been investigated. Administration of hemin increases the steady-state level of ferritin mRNA about 10-fold and that of ferritin protein expression 20-fold. Experiments with the transcriptional inhibitor actinomycin D and transfection studies demonstrate that the increment in cytoplasmic mRNA content results from enhanced transcription of the ferritin H-chain gene and cannot be attributed to stabilization of preexisting mRNAs. In addition to transcriptional effects, translational regulation induces the recruitment of stored mRNAs into functional polyribosomes after hemin and FAC administration, resulting in a further increase in ferritin synthesis. Administration of protoporphyrin IX to FLCs produces divergent transcriptional and translational effects. It increases transcription but appears to suppress ferritin mRNA translation. FAC treatment increases the mRNA content slightly (about twofold), and the ferritin levels rise about fivefold over the control values. We conclude that in FLCs, hemin induces ferritin H-chain biosynthesis by multiple mechanisms: a transcriptional mechanism exerted also by protoporphyrin IX and a translational one, not displayed by protoporphyrin IX but shared with FAC.
57 citations
TL;DR: The br c-1 mutant, which also accumulates protoporphyrin in the dark, forms chlorophyll and chloroplast lamellae when transferred to the light, showing that function of the porphyr in pathway is normal in the light.
Abstract: In this report we describe two nonallelic Mendelian protoporphyrin accumulating mutants brs-1 and brc-1. Results of experiments with these mutants lead us to postulate that porphyrin biosynthesis branches into light and dark steps between protoporphyrin-IX and magnesium protoporphyrin. We hypothesize that the brc locus controls a dark step while the brs locus either controls a step in the main pathway before the branch or mediates the preparation of the magnesium ion for its insertion into protoporphyrin-IX. The brs-1 mutant is thought to be light sensitive because a block prior to the branch point in the porphyrin pathway prevents chlorophyll formation in either the light or the dark. The brc-1 mutant, which also accumulates protoporphyrin in the dark, forms chlorophyll and chloroplast lamellae when transferred to the light, showing that function of the porphyrin pathway is normal in the light.
57 citations
TL;DR: The aim of this work is the synthesis of a new family of glycosylated porphyrins in which the sugar moieties are linked to the tetrapyrrole ring by a thioglycosidic bond.
57 citations
TL;DR: Results suggested that porphyrin accumulation in mitochondria is mediated by OGC and that p Morphyrins are able to competitively inhibit 2-oxoglutarate uptake into mitochondria, the first report of a putative mechanism for accumulation of porphyrs in the mitochondrial inner membrane.
57 citations