Butafenacil is an herbicide that inhibits protoporphyrinogen oxidase (PPOX), an enzyme that catalyzes oxidation of protoporphyrinogen IX to protoporphyrin IX during chlorophyll and heme biosynthesis. Based on a high-content screen, we previously identified butafenacil as a potent inducer of anemia in zebrafish embryos. Therefore, the objective of this study was to begin investigating the utilit...

In August 1997 we performed a follow-up survey of 146 lead-poisoned children from a community near a previously active auto battery recycling smelter in Haina near Santo Domingo, Dominican Republic. Our follow-up survey confirmed a severe incidence of elevated blood lead (BPb) and erythrocyte protoporphyrin/zinc protoporphyrin (EP-ZnPP) levels. The mean BPb level was 32 micrograms/dL and the me...

1. We have studied the kinetics of the conversion of 5-aminolaevulinate into haem and haem precursors in homogenates of livers of rats and chick embryos. Homogenates of fresh liver from both species efficiently convert 5-aminolaevulinate into haem. After frozen storage for 1 year, homogenates of rat, but not chick, liver have decreased rates of formation of haem with accumulation of more protop...

In erythropoietic protoporphyria, accumulation of protoporphyrin has been found in various tissues and liver cirrhosis occurs frequently in this disease, probably due to toxic dark effects of protoporphyrin. We have studied the effect of porphyrins on various enzymic functions in rat liver microsomes. Incubation of microsomes with protoporphyrin resulted in a concentration-dependent inhibition ...

The photosynthetic gene cluster of R sphaeroides is encoded on a 45kb region of the genome and is represented by 8 overlapping inserts cloned in the mobilisable vector pSUP202 [ l ] . Characterisation of the cluster by a variety of techniques, including complementation analyses and study of accumulated products of bacteriochlorophyll synthesis in mutants, provides a physical map (Figure 1) and ...

Protoporphyrin (IX) ferrochelatase catalyses the insertion of ferrous iron into protoporphyrin IX to form haem. These ferrochelatases exist as monomers and dimers, both with and without [2Fe-2S] clusters. The motifs for [2Fe-2S] cluster co-ordination are varied, but in all cases previously reported, three of the four cysteine ligands are present in the 30 C-terminal residues and the fourth liga...

Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis caused by partial ferrochelatase deficiency, resulting in protoporphyrin overproduction which is responsible for painful skin photosensitivity. Chronic liver disease is the most severe complication of EPP, requiring liver transplantation in some patients. Data from a mouse model suggest that cytotoxic bile formati...

Shemin and coworkers (14) showed that the a-carbon and nitrogen atoms of glycine were precursors of specific atoms of the heme molecule. This was substantiated by Muir and Neuberger (5, 6). Other carbon atoms were shown to come from acetate (5-7) or succinate (8). The nature of the intermediate precursors synthesized from these metabolites remained unknown until the structure for urinary porpho...

Protoporphyrin IX is an activator of soluble guanylate cyclase (sGC), but its role as an endogenous regulator of vascular function through cGMP has not been previously reported. In this study we examined whether the heme precursor delta-aminolevulinic acid (ALA) could regulate vascular force through promoting protoporphyrin IX-elicited activation of sGC. Exposure of endothelium-denuded bovine p...