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Protoporphyrins
About: Protoporphyrins is a research topic. Over the lifetime, 145 publications have been published within this topic receiving 3486 citations.
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TL;DR: The hepatic pigment accumulated in 3,5-diethoxycarbonyl-1,4-dihydrocollidine-treated rats, which has been reported to inhibit ferrochelatase, has been isolated and purified and the four isomers of N-methylprotoporphyrin IX have been chemically synthesized, independently characterized, and used to confirm the structures of the biologically products.
Abstract: The hepatic pigment accumulated in 3,5-diethoxycarbonyl-1,4-dihydrocollidine-treated rats, which has been reported to inhibit ferrochelatase, has been isolated and purified. The pigment has been resolved into one major, one minor, and two trace components, all of which appear to be isomeric porphyrins. The major fraction has been unambiguously identified by spectroscopic methods as the isomer of N-methylprotoporphyrin IX (isolated as the dimethyl ester) in which vinyl-substituted pyrrole ring A is methylated. The minor product appears to be an isomer of the same porphyrin with the N-methyl group on propionic acid-substituted ring C, and the trace components have the same high-pressure liquid chromatography retention times as the other two possible isomers of the porphyrin. The four isomers of N-methylprotoporphyrin IX have been chemically synthesized, independently characterized, and used to confirm the structures of the biologically products.
63 citations
62 citations
TL;DR: This paper showed that porphobilinogen is a highly specific precursor of porphyrins and showed that it can be formed by condensation of two molecules of δ-aminolaevulinic acid.
Abstract: WE showed recently1 that porphobilinogen is a highly specific precursor of porphyrins, and Shemin and Russell2 have presented evidence that δ-aminolaevulinic acid is a specific precursor of haem. Shemin and Russell's finding has been confirmed independently in our system (cf. Neuberger and Scott3) to the extent that, on incubation with a chicken red cell haemolysate4, δ-aminolaevulinic acid is converted to uro-, copro- and protoporphyrins. The yield of each of these porphyrins from δ-aminolaevulinic acid was, moreover, identical to that1 from an equivalent amount of porphobilinogen. The structure of porphobilinogen5 suggests that this compound could be formed by the condensation of two molecules of δ-aminolaevulinic acid (see also refs. 2 and 3), and the equivalence of the two compounds with respect to porphyrin formation may be taken as support for this idea. We now present evidence indicating the occurrence of such a condensation in the chicken red cell haemolysate.
61 citations
49 citations
TL;DR: Overall, these values were not statistically different from values for a control group of specimens from fifty ambulatory dermatology patients, however, they were, on average, lower than the normal values previously determined for the method used.
Abstract: Plasma porphyrins and free erythrocyte protoporphyrins were measured in sixty-two chronic hemodialysis patients. Plasma porphyrins were significantly elevated in these patients and overlapped the lower portion of the range observed in twenty-four patients with porphyria cutanea tarda. Free erythrocyte protoporphyrins were moderately elevated in four patients. Overall, these values were not statistically different from values for a control group of specimens from fifty ambulatory dermatology patients. However, they were, on average, lower than the normal values previously determined for the method used.
45 citations