Showing papers on "Protoporphyrin IX published in 1979"

Chloroplast Biogenesis: XXIV. Intrachloroplastic Localization of the Biosynthesis and Accumulation of Protoporphyrin IX, Magnesium-Protoporphyrin Monoester, and Longer Wavelength Metalloporphyrins during Greening.

Abstract: The intraplastidic localization of the endogenous metabolic pools from protoporphyrin to protochlorophyll was determined in Cucumis sativus. The endogenous protoporphyrin, Mg-protoporphyrin monoester + longer wavelength metalloporphyrins, protochlorophyllide and protochlorophyllide ester were membrane-bound. Protoporphyrin was synthesized in the stroma and subsequently became associated with the membranes. The membrane-associated protoporphyrin was then converted into Mg-protoporphyrin monoester + longer wavelength metalloporphyrins by membrane-bound enzymes. Although lysed plastids were capable of converting exogenous δ-aminolevulinic acid to protochlorophyllide, the net synthesis of protochlorophyllide from exogenous δ-aminolevulinic acid was lost upon segregating the lysed plastids into stromal and membrane fractions and then recombining the stromal and membrane fraction prior to incubation. The segregated membrane fraction was still capable of converting protoporphyrin into Mg-protoporphyrin monoester + longer wavelength metalloporphyrins in the presence or absence of the stromal fraction. These results indicated that although the reactions from protoporphyrin to Mg-protoporphyrin monoester and longer wavelength metalloporphyrins could survive a considerable degree of plastid disruption, the reactions from Mg-protoporphyrin monoester and longer wavelength metalloporphyrins to protochlorophyllide were more sensitive to structural disorganization.

Copper(II) protoporphyrin IX as a reporter group for the heme environment in myoglobin.

Abstract: Copper(II) protoporphyrin IX has been introduced into apomyoglobin, and its utility as a reporter group of the heme environment has been examined. The Soret and visible absorption bands and electron spin resonance spectrum show that the Cu(II) is five coordinate, probably through coordination to the F-8 proximal histidine. The resonance Raman spectrum does not indicate any appreciable distortion from the solution conformation of copper(II) protoporphyrin IX dimethyl ester in CS2. The ultraviolet circular dichroism shows no alteration of the helical content of the globin from that of metmyoglobin. The circular dichroism of the porphyrin transitions suggests that the packing of the amino acid side chains around the porphyrin is different than that in the native metmyoglobin.

Separation of protoporphyrins and related compounds by reversed-phase liquid chromatography.

Abstract: We describe the separation of protoporphyrin and related porphyrins by reversed-phase "high-performance" liquid chromatography, with fluorometric detection. We used the method to demonstrate that acid hydrolysis of the dimethyl ester of protoporphyrin IX is complete in 2 to 3 h and is followed by the acid-catalyzed conversion of protoporphyrin IX to a chemical species that chromatographic evidence indicates to be hematoporphyrin IX. In addition, the method was used to evaluate the purity of a commercial preparation of protoporphyrin IX and was also demonstrated to have the sensitivity and specificity needed for measuring the protoporphyrin IX content of whole-blood.

Effect of hemin and Protoporphyrin IX on the protein-synthesizing activity of human granulocytes, lymphocytes and platelets.

Abstract: The hemin effect on protein synthesis of human granulocytes, lymphocytes and platelets was examined. Hemin added to culture media without serum caused a dose-dependent inhibition of protein synthesis

Role of oxygen radicals scavenging enzymes in the protoporphyrin induced photohemolysis.

Abstract: Inhibition of superoxide dismutase by diethyldithiocarbamate or cyanide increases the rate of red blood cells lysis after irradiation in the presence of protoporphyrin IX. Catalase activity, which is decreased during the photohemolytic process, appears to be not essential for the lytic event. No relationship between catalase activity and hemolysis rate was found. Superoxide dismutase appears to prevent only in part catalase inactivation by singlet oxygen.

Studies in porphyria IX: Detection of the gene defect of erythropoietic protoporphyria in mitogen-stimulated human lymphocytes.

Abstract: We have demonstrated in this study that mitogen-stimulated lymphocytes from EPP subjects accumulate substantially greater amounts of protoporphyrin IX than do normal lymphocytes when incubated with ALA. Protoporphyrin IX formation by normal lymphocytes is stimulated by CaMgEDTA, an inhibitor of ferrochelatase, and is decreased by ferrous iron which facilitates the utilization of protoporphyrin IX for heme synthesis. In contrast, protoporphyrin IX formation by EPP lymphocytes is less stimulated by CaMgEDTA than is the case with normal lymphocytes and is only slightly affected by iron. Clinically manifested EPP subjects and completely latent gene carriers of EPP can be identified using this lymphocyte culture technique. The data from this study provide clear evidence of a functional deficiency of ferrochelatase activity in human EPP lymphocytes. EPP thus represents the third of the three dominant porphyric disorders of man, including acute intermittent porphyria and hereditary coproporphyria, which can now be diagnosed using lymphocytes.

Electrophilic attack at the porphyrin periphery. meso-vs. β-Deuteriation

Abstract: Deuteroporphyrin IX undergoes faster deuteriation at the meso-positions than at the β-positions in deuterioacetic acid whilst in its metal complexes the order is reversed; protoporphyrin IX undergoes deuteriation at the meso-position in preference to the vinyl positions.