Showing papers on "Protoporphyrins published in 1981"

N-Methylprotoporphyrin IX: chemical synthesis and identification as the green pigment produced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine treatment

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.

beta-meso-Phenylbiliverdin IX alpha and N-phenylprotoporphyrin IX, products of the reaction of phenylhydrazine with oxyhemoproteins.

Abstract: Oxyhemoglobin and oxymyoglobin were allowed to react aerobically with phenylhydrazine and p-tolylhydrazine. The chloroform extract of each reaction mixture, after treatment with H2SO4/methanol, yielded a blue pigment and a green pigment, which were identified by electronic absorption, mass, and proton NMR spectroscopy as the dimethyl esters of beta-meso-arylbiliverdin IX alpha and N-arylprotoporphyrin IX, respectively. N-Phenylprotoporphyrin IX dimethyl ester formed complexes with Zn2+, Cd2+, and Hg2+ but not with other cations. The proton NMR spectrum of the zinc complex suggested binding of the phenyl group to one of the two pyrrole rings of protoporphyrin IX with a propionic acid substituent. The effectiveness of phenylhydrazine as an inducer of Heinz body formation may be due to destabilization of the hemoglobin molecule by the replacement of heme with phenyl adducts of biliverdin and protoporphyrin.

Acid—base properties of protoporphyrin IX; its dimethyl ester and heme solubilized on surfactant micelles: spectrophotometric and fluorometric titration

Abstract: Absorption and fluorescence spectra have been obtained and spectrophotometric and fluorometric titration curves recorded for protoporphyrin IX (H2P(COOH)2) and its dimethyl ester (H2P(COOCH3)2) in their aqueous solutions, in Triton X-100 and cetyl trimethylammonium bromide (CTAB) micelles. The spectrophotometric titration of heme in Triton X-100 micelles has been performed. The pK of protoporphyrin pyrrole nitrogens were equal to about 6.5 in water solution and to 0.8 and 0.7 in Triton X-100 and CTAB micelles, respectively. The hematin-hemin pK was 3.75 in Triton X-100 micelles. The pK shifts were explained as due to the low effective dielectric constant in Triton X-100 and CTAB micelle nuclei. The pK values of propionic acid residues were determined for H2P(COOH)2 and heme in the micelles. A considerable decrease in the critical micelle concentration of surfactants in the presence of protoporphyrins has been observed. It has been suggested that the porphyrin macrocycle is located in the micelle nucleus whereas the propionic acid residues are in the Stern layer.

Achieving and Maintaining Moderate Iron Deficiency in Rats

Abstract: A method for achieving and maintaining moderate levels of nutritional iron deficiency in the male albino rat is described. Hemoglobin concentrations and protoporphyrin/heme ratios were the parameters used to assess iron status. The method was based upon the age of the animals when iron-deficient conditions were introduced.