Showing papers on "Porphyrin published in 1968"
406 citations
98 citations
TL;DR: The enzymic activities of these synthetic enzymes in the peroxidatic oxidation offerrocytochrome c, ferrocyanide, and ascorbate were found to be quite similar, indicating that the side chains of porphyrin IX at positions 2 and 4 were not essential for the catalytic activity of cy tochrome c peroxIDase.
62 citations
Journal Article•
54 citations
TL;DR: In this paper, it was shown that the porphyrin phosphorescent triplet gives rise to a trip doublet and a quartet state, while the octalkyl porphin is quartet at both temperatures.
47 citations
44 citations
TL;DR: Several porphyrin derivatives containing rhodium and iridium have been prepared by two different methods as mentioned in this paper, and the compounds were characterized by elemental analysis, mass spectrum, infrared spectrum, visible absorption spectrum, and magnetic susceptibility measurements.
36 citations
TL;DR: Erythropoietic protoporphyria (EPP) is an inherited photocutaneous disorder that includes cutaneous photosensitivity, greatly increased erythrocyte and fecal protoporphyrin, and a variable but often marked increase in plasma protopoiryrin.
Abstract: Erythropoietic protoporphyria (EPP) is an inherited photocutaneous disorder first described in 19611The typical syndrome includes cutaneous photosensitivity, greatly increased erythrocyte and fecal protoporphyrin, and a variable but often marked increase in plasma protoporphyrin The urine is normal Although the photosensitivity is clearly due to protoporphyrin, the site of formation of this porphyrin has been questioned Initially it was suggested that the photosensitivity was associated with the high red cell porphyrin However, in keeping with the other cutaneous porphyrias, increased porphyrin in the plasma was subsequently demonstrated2,3The possibility that the plasma porphyrin causes the photosensitivity and is synthesized at a nonerythropoietic site was suggested by Redeker and Bryan in 19644 The rate-limiting enzyme for porphyrin biosynthesis is aminolevulinic acid synthetase (ALA-S) Hepatic ALA-S is an inducible enzyme in patients with acute intermittent porphyria (AIP) and its rate of synthesis is reciprocal with carbohydrate or protein intake
32 citations
Journal Article•
31 citations
TL;DR: In this article, the conjugated electron system of chlorophyll and its derivatives has been studied for the first time and the final question of stereochemistry at the carbons 7 and 8 has been settled by Fleming.
Abstract: Following the isolation and elucidation of the structure of a natural compound there remain two additional goals: total synthesis and last, but not least, a deeper understanding of the molecule at hand by means of a closer study. Chlorophyll, the green pigment of the plant kingdom, being in the first instance responsible for transforming light energy into chemical reactivity with the ultimate production of starch, and haeme, the red blood pigment which secures the transport of oxygen for maintaining respiration, have aroused the interest of scientists for more than 100 years. The names of Borodin, Willstätter, H. Fischer, Stoll, Conant, Linstead, and others are associated with isolation, structural problems, and a vast amount of primary chemical knowledge in this fieldl. Woodward and his team2 achieved the enormous task of the total synthesis of chlorophyll a in 1960. And lately the final question of stereochemistry at the carbons 7 and 8 has been settled by Fleming3. For about 10 years scientists have tried with renewed intensity to learn more about this fascinating compound, naturally with the help of modern chemical and physical methods. To understand better the properties of chlorophyll and its derivatives a closer knowledge of its conjugated electron system seems important.
22 citations
TL;DR: In this paper, the peak position of the Soret band (λ p) was used to determine the number of carboxylic groups in a porphyrin mixture.
TL;DR: In this article, the kinetics of the formation of Mn(III) hematoporphyrin in glacial acetic acid has been studied spectrophotometrically.
Abstract: The kinetics of the formation of Mn(III) hematoporphyrin in glacial acetic acid has been studied spectrophotometrically.On addition of Mn(II) to porphyrin in glacial acetic acid a species which app...
TL;DR: Equations were derived which correct for impuritie(s) isolated with the porphyrins from red cell hemolysates and the need for extensive purification of the p Morphyrin solutions was eliminated.
TL;DR: The results of polarography and cyclic voltammetry studies of hematoporphyrin IX with eight different added ligands (other than H2O and OH−) in aqueous solvent are reported as mentioned in this paper.
Abstract: The results of polarography and cyclic voltammetry studies of hematoporphyrin IX with eight different added ligands (other than H2O and OH−) in aqueous solvent are reported. Two nitrogenous ligand molecules were found to coordinate with both manganese (III) and manganese(II) hematoporphyrin IX. Oxygenated ligands such as acetate and pyrophosphate showed no tendency to coordinate with either manganese (III) or manganese (II) porphyrin. Porphyrin adsorption on the mercury electrode is quite evident. The adsorption mechanism appears to be complicated.
Abstract: Our stepwise porphin synthesis has been used for the preparation of three porphins, including deuterioporphyrin IX dimethyl ester, containing one or two unsubstituted β-positions, and three β-vinylporphins, including pemptoporphyrin dimethyl ester and spirographis porphyrin dimethyl ester. The vinyl substituents have been introduced through β-dimethylaminoethyl groups by Hofmann degradations.
TL;DR: In this article, the electron capture method was applied to meso-porphyrin IX dimethyl esters, metal-free phthalocyanine, chlorophyll, riboflavine, nicotinamide, tetracene, and pentacene.
Abstract: The electron capture method was applied to protoporphyrin IX and meso- porphyrin IX dimethyl esters, metal-free phthalocyanine, chlorophyll, riboflavine, nicotinamide, tetracene, and pentacene. The energy quantities obtained correlated with calculated energies of the lowest empty molecular orbitals of these molecules.
TL;DR: As indicated by glycine-2-14C incorporation into free porphyrin, heme, or both, the tissues, except possibly heart, synthesized porphirin in vitro, and correlation between p Morphyrin synthesis and concentration was positive and significant.
Abstract: Summary Proto- and coproporphyrin concentrations in Pekin duck tissues were determined. The tissues and corresponding protoporphyrin concentrations (mμmole/kg) were erythrocytes (1200), liver (500), heart (410), gizzard (400), intestine (330), kidney (250), spleen (220), breast muscle (170), brain (88), and testes (42). The ratio of proto- to coproporphyrin concentrations ranged from 5 in liver to 22 in erythrocytes. The porphyrin concentrations were not significantly correlated. As indicated by glycine-2-14C incorporation into free porphyrin, heme, or both, the tissues, except possibly heart, synthesized porphyrin in vitro. Correlation between porphyrin synthesis and concentration was positive and significant.
TL;DR: The findings are consistent with hypothesis as follows: Porphyrin is bound to a particulate component of the erythrocyte at synthesis and later appears in the soluble phase of the cell.