Spectroscopy of Porphyrins

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Electronic Spectroscopy of Free Base Porphyrins and Metalloporphyrins

Absorption and Fluorescence Spectroscopy of Tetraphenylporphyrin§ and Metallo-Tetraphenylporphyrin Introduction The word porphyrin is derived from the Greek porphura meaning purple, and all porphyrins are intensely coloured1. Porphyrins comprise an important class of molecules that serve nature in a variety of ways. The Metalloporphyrin ring is found in a variety of important biological system where it is the active component of the system or in some ways intimately connected with the activity of the system. Many of these porphyrins synthesized are the basic structure of biological porphyrins which are the active sites of numerous proteins, whose functions range from oxygen transfer and storage (hemoglobin and myoglobin) to electron transfer (cytochrome c, cytochrome oxidase) to energy conversion (chlorophyll). They also have been proven to be efficient sensitizers and catalyst in a number of chemical and photochemical processes especially photodynamic therapy (PDT). The diversity of their functions is due in part to the variety of metals that bind in the “pocket” of the porphyrin ring system (Fig. 1). Figure 1. Metallated Tetraphenylporphyrin Upon metalation the porphyrin ring system deprotonates, forming a dianionic ligand (Fig. 2). The metal ions behave as Lewis acids, accepting lone pairs of electrons ________________________________ § We all need to thank Jay Stephens for synthesizing the H2TPP 2 from the dianionic porphyrin ligand. Unlike most transition metal complexes, their color is due to absorption(s) within the porphyrin ligand involving the excitation of electrons from π to π* porphyrin ring orbitals. Figure 2. Synthesis of Zn(TPP) The electronic absorption spectrum of a typical porphyrin consists of a strong transition to the second excited state (S0 S2) at about 400 nm (the Soret or B band) and a weak transition to the first excited state (S0 S1) at about 550 nm (the Q band).
Porphyrins & Bile Pigments

Bio. 2. ASPU. Lectu.6. Prof. Dr. F. ALQuobaili Porphyrins & Bile Pigments • Biomedical Importance These topics are closely related, because heme is synthesized from porphyrins and iron, and the products of degradation of heme are the bile pigments and iron. Knowledge of the biochemistry of the porphyrins and of heme is basic to understanding the varied functions of hemoproteins in the body. The porphyrias are a group of diseases caused by abnormalities in the pathway of biosynthesis of the various porphyrins. A much more prevalent clinical condition is jaundice, due to elevation of bilirubin in the plasma, due to overproduction of bilirubin or to failure of its excretion and is seen in numerous diseases ranging from hemolytic anemias to viral hepatitis and to cancer of the pancreas. • Metalloporphyrins & Hemoproteins Are Important in Nature Porphyrins are cyclic compounds formed by the linkage of four pyrrole rings through methyne (==HC—) bridges. A characteristic property of the porphyrins is the formation of complexes with metal ions bound to the nitrogen atom of the pyrrole rings. Examples are the iron porphyrins such as heme of hemoglobin and the magnesium‐containing porphyrin chlorophyll, the photosynthetic pigment of plants. • Natural Porphyrins Have Substituent Side Chains on the Porphin Nucleus The porphyrins found in nature are compounds in which various side chains are substituted for the eight hydrogen atoms numbered in the porphyrin nucleus. As a simple means of showing these substitutions, Fischer proposed a shorthand formula in which the methyne bridges are omitted and a porphyrin with this type of asymmetric substitution is classified as a type III porphyrin.
Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses

life Review Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses Inseok Choi , Hyewon Son and Jea-Hyun Baek * School of Life Science, Handong Global University, Pohang, Gyeongbuk 37554, Korea; [email protected] (I.C.); [email protected] (H.S.) * Correspondence: [email protected]; Tel.: +82-54-260-1347 Abstract: The tricarboxylic acid cycle (TCA) is a series of chemical reactions used in aerobic organisms to generate energy via the oxidation of acetylcoenzyme A (CoA) derived from carbohydrates, fatty acids and proteins. In the eukaryotic system, the TCA cycle occurs completely in mitochondria, while the intermediates of the TCA cycle are retained inside mitochondria due to their polarity and hydrophilicity. Under cell stress conditions, mitochondria can become disrupted and release their contents, which act as danger signals in the cytosol. Of note, the TCA cycle intermediates may also leak from dysfunctioning mitochondria and regulate cellular processes. Increasing evidence shows that the metabolites of the TCA cycle are substantially involved in the regulation of immune responses. In this review, we aimed to provide a comprehensive systematic overview of the molecular mechanisms of each TCA cycle intermediate that may play key roles in regulating cellular immunity in cell stress and discuss its implication for immune activation and suppression. Keywords: Krebs cycle; tricarboxylic acid cycle; cellular immunity; immunometabolism 1. Introduction The tricarboxylic acid cycle (TCA, also known as the Krebs cycle or the citric acid Citation: Choi, I.; Son, H.; Baek, J.-H. Tricarboxylic Acid (TCA) Cycle cycle) is a series of chemical reactions used in aerobic organisms (pro- and eukaryotes) to Intermediates: Regulators of Immune generate energy via the oxidation of acetyl-coenzyme A (CoA) derived from carbohydrates, Responses.
Citric Acid Cycle

CHEM464 / Medh, J.D. The Citric Acid Cycle Citric Acid Cycle: Central Role in Catabolism • Stage II of catabolism involves the conversion of carbohydrates, fats and aminoacids into acetylCoA • In aerobic organisms, citric acid cycle makes up the final stage of catabolism when acetyl CoA is completely oxidized to CO2. • Also called Krebs cycle or tricarboxylic acid (TCA) cycle. • It is a central integrative pathway that harvests chemical energy from biological fuel in the form of electrons in NADH and FADH2 (oxidation is loss of electrons). • NADH and FADH2 transfer electrons via the electron transport chain to final electron acceptor, O2, to form H2O. Entry of Pyruvate into the TCA cycle • Pyruvate is formed in the cytosol as a product of glycolysis • For entry into the TCA cycle, it has to be converted to Acetyl CoA. • Oxidation of pyruvate to acetyl CoA is catalyzed by the pyruvate dehydrogenase complex in the mitochondria • Mitochondria consist of inner and outer membranes and the matrix • Enzymes of the PDH complex and the TCA cycle (except succinate dehydrogenase) are in the matrix • Pyruvate translocase is an antiporter present in the inner mitochondrial membrane that allows entry of a molecule of pyruvate in exchange for a hydroxide ion. 1 CHEM464 / Medh, J.D. The Citric Acid Cycle The Pyruvate Dehydrogenase (PDH) complex • The PDH complex consists of 3 enzymes. They are: pyruvate dehydrogenase (E1), Dihydrolipoyl transacetylase (E2) and dihydrolipoyl dehydrogenase (E3). • It has 5 cofactors: CoASH, NAD+, lipoamide, TPP and FAD. CoASH and NAD+ participate stoichiometrically in the reaction, the other 3 cofactors have catalytic functions.
Emerging Applications of Porphyrins and Metalloporphyrins in Biomedicine and Diagnostic Magnetic Resonance Imaging

biosensors Review Emerging Applications of Porphyrins and Metalloporphyrins in Biomedicine and Diagnostic Magnetic Resonance Imaging Muhammad Imran 1,*, Muhammad Ramzan 2,*, Ahmad Kaleem Qureshi 1, Muhammad Azhar Khan 2 and Muhammad Tariq 3 1 Department of Chemistry, Baghdad-Ul-Jadeed Campus, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan; [email protected] 2 Department of Physics, Baghdad-Ul-Jadeed Campus, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan; [email protected] 3 Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800, Pakistan; [email protected] * Correspondence: [email protected] (M.I.); [email protected] (M.R.) Received: 26 September 2018; Accepted: 17 October 2018; Published: 19 October 2018 Abstract: In recent years, scientific advancements have constantly increased at a significant rate in the field of biomedical science. Keeping this in view, the application of porphyrins and metalloporphyrins in the field of biomedical science is gaining substantial importance. Porphyrins are the most widely studied tetrapyrrole-based compounds because of their important roles in vital biological processes. The cavity of porphyrins containing four pyrrolic nitrogens is well suited for the binding majority of metal ions to form metalloporphyrins. Porphyrins and metalloporphyrins possess peculiar photochemical, photophysical, and photoredox properties which are tunable through structural modifications. Their beneficial photophysical properties, such as the long wavelength of emission and absorption, high singlet oxygen quantum yield, and low in vivo toxicity, have drawn scientists’ interest to discover new dimensions in the biomedical field. Applications of porphyrins and metalloporphyrins have been pursued in the perspective of contrast agents for magnetic resonance imaging (MRI), photodynamic therapy (PDT) of cancer, bio-imaging, and other biomedical applications.
Vitamin B12 Promotes Porphyrin Production in Acne-Associated P

UCLA UCLA Electronic Theses and Dissertations Title Porphyrin production and regulation in different Propionibacterium acnes lineages contribute to acne vulgaris pathogenesis Permalink https://escholarship.org/uc/item/9g02d15m Author Johnson, Tremylla Publication Date 2017 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA Los Angeles Porphyrin production and regulation in different Propionibacterium acnes lineages contribute to acne vulgaris pathogenesis A dissertation submitted in partial satisfaction of the requirement for the degree Doctor of Philosophy in Molecular and Medical Pharmacology by Tremylla A. Johnson 2017 © Copyright by Tremylla A. Johnson 2017 ABSTRACT OF THE DISSERTATION Porphyrin production and regulation in different Propionibacterium acnes lineages contribute to acne vulgaris pathogenesis by Tremylla A. Johnson Doctor of Philosophy in Molecular & Medical Pharmacology University of California, Los Angeles, 2017 Professor Huiying Li, Chair Propionibacterium acnes is a dominant human skin commensal. It has been implicated in acne pathogenesis, but its role remains unclear. Recent metagenomic studies have revealed that certain P. acnes strains are highly associated with acne, while some others are associated with healthy skin. Little information exists about P. acnes strain-level differences beyond the genomic differences. In this study, I revealed that acne-associated type IA P. acnes strains produced significantly higher levels of porphyrins (a metabolite important in acne development) than health-associated strains (type II). Strains of type IA-1 and type IA-2 produced similar levels of porphyrins. Moreover, porphyrin production in these P. acnes strains is modulated by vitamin B12. On the other hand, health-associated type II strains produced low levels of ii porphyrins and did not respond to vitamin B12.
Expanding the Eggshell Colour Gamut: Uroerythrin and Bilirubin from Tinamou (Tinamidae) Eggshells Randy Hamchand1, Daniel Hanley2, Richard O

www.nature.com/scientificreports OPEN Expanding the eggshell colour gamut: uroerythrin and bilirubin from tinamou (Tinamidae) eggshells Randy Hamchand1, Daniel Hanley2, Richard O. Prum3 & Christian Brückner1* To date, only two pigments have been identifed in avian eggshells: rusty-brown protoporphyrin IX and blue-green biliverdin IXα. Most avian eggshell colours can be produced by a mixture of these two tetrapyrrolic pigments. However, tinamou (Tinamidae) eggshells display colours not easily rationalised by combination of these two pigments alone, suggesting the presence of other pigments. Here, through extraction, derivatization, spectroscopy, chromatography, and mass spectrometry, we identify two novel eggshell pigments: yellow–brown tetrapyrrolic bilirubin from the guacamole- green eggshells of Eudromia elegans, and red–orange tripyrrolic uroerythrin from the purplish-brown eggshells of Nothura maculosa. Both pigments are known porphyrin catabolites and are found in the eggshells in conjunction with biliverdin IXα. A colour mixing model using the new pigments and biliverdin reproduces the respective eggshell colours. These discoveries expand our understanding of how eggshell colour diversity is achieved. We suggest that the ability of these pigments to photo- degrade may have an adaptive value for the tinamous. Birds’ eggs are found in an expansive variety of shapes, sizes, and colourings 1. Te diverse array of appearances found across Aves is achieved—in large part—through a combination of structural features, solid or patterned colorations, the use of two diferent dyes, and diferential pigment deposition. Eggshell pigments are embedded within the white calcium carbonate matrix of the egg and within a thin outer proteinaceous layer called the cuticle2–4. Tese pigments are believed to play a key role in crypsis5,6, although other, possibly dynamic 7,8, roles in inter- and intra-species signalling5,9–12 are also possible.
To a Protoporphyrin. Thus, Type I Porphyrinogens Or Their Respective Porphyrins Reduced Production Oftype III Porphyrin and Hemo

A SUGGESTED CONTROL GENE MECHANISM FOR THE EXCESSIVE PRODUCTION OF TYPES I AND III PORPHYRINS IN CONGENJ TAL ERYTHROPOIETIC PORPHYRIA* BY C. J. WATSON, W. RUNGE, L. TADDEINI, IRENE BOSSENMAIER, AND RUTH CARDINAL DEPARTMENT OF MEDICINE, UNIVERSITY OF MINNESOTA, MINNEAPOLIS Communicated June 19, 1964 The curious phenotype of erythropoietic porphyria, both human and bovine, is directly related to the large amounts of type I porphyrins produced by the develop- ing red cells of the bone marrow. The excessive uroporphyrin (URO-) I is respon- sible for the photocutaneous manifestations, as well as the red urine, teeth, and bones. The spleen enlarges and is at least partly responsible for the increased destruction of circulating red cells so often observed. This stimulates erythro- poiesis and heightened formation of porphyrins, as described elsewhere.1-3 It has been proposed4-7 that the genetic error is a deficiency of uroporphyrinogen (UPG) isomerase. This enzyme directs cyclization to UPG III, of the polypyrryl methane first formed from porphobilinogen (PBG) by PBG deaminase. UPG III is preferentially converted by a decarboxylase to coproporphyrinogen (CPG) III and this by virtue of a coproporphyrinogenase (CPGase), to the corresponding protoporphyrin (PROTO-) and heme. In the absence or relative paucity of isomerase the polypyrryl methane from PBG cyclizes to UPG I, and is decarboxyl- ated in varying proportion to CPG I. With possible rare and minor exceptions,8 the specificity of CPGase for type III is maintained, and CPG-I is not converted to a protoporphyrin. Thus, type I porphyrinogens or their respective porphyrins are excreted or accumulated. This has been discussed in recent reviews.4-7 If the inborn error were an isomerase deficiency, a markedly reduced production of type III porphyrin and hemoglobin might be anticipated.
Biliverdin Reductase: a Major Physiologic Cytoprotectant

Biliverdin reductase: A major physiologic cytoprotectant David E. Baran˜ ano*, Mahil Rao*, Christopher D. Ferris†, and Solomon H. Snyder*‡§¶ Departments of *Neuroscience, ‡Pharmacology and Molecular Sciences, and §Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; and †Department of Medicine, Division of Gastroenterology, C-2104 Medical Center North, Vanderbilt University Medical Center, Nashville, TN 37232-2279 Contributed by Solomon H. Snyder, October 16, 2002 Bilirubin, an abundant pigment that causes jaundice, has long hypothesize that bilirubin acts in a catalytic fashion whereby lacked any clear physiologic role. It arises from enzymatic reduction bilirubin oxidized to biliverdin is rapidly reduced back to bili- by biliverdin reductase of biliverdin, a product of heme oxygenase rubin, a process that could readily afford 10,000-fold amplifica- activity. Bilirubin is a potent antioxidant that we show can protect tion (13). Here we establish that a redox cycle based on BVRA cells from a 10,000-fold excess of H2O2. We report that bilirubin is activity provides physiologic cytoprotection as BVRA depletion a major physiologic antioxidant cytoprotectant. Thus, cellular de- exacerbates the formation of reactive oxygen species (ROS) and pletion of bilirubin by RNA interference markedly augments tissue augments cell death. levels of reactive oxygen species and causes apoptotic cell death. Depletion of glutathione, generally regarded as a physiologic Methods antioxidant cytoprotectant, elicits lesser increases in reactive ox- All chemicals were obtained from Sigma unless otherwise ygen species and cell death. The potent physiologic antioxidant indicated. actions of bilirubin reﬂect an ampliﬁcation cycle whereby bilirubin, acting as an antioxidant, is itself oxidized to biliverdin and then Cell Culture and Viability Measurements.
The Porphyrin Handbook

ThePorphyrinHandbook Editors KarlM.Kadish DepartmentofChemistry UniversityofHouston Houston,Texas KevinM.Smith DepartmentofChemistry UniversityofCalifornia,Davis Davis,California RogerGuilard FaculteÂdesSciencesGabriel UniversiteÂdeBourgogne Dijon,France SANDIEGOSANFRANCISCO NEWYORKBOSTON LONDONSYDNEY TORONTO Preface The broadly de®ned porphyrin research area is one of the this is a data-intensive ®eld, and we believe that compilation most exciting, stimulating and rewarding for scientists in the of relevant data should be useful to investigators. We have ®elds of chemistry, physics, biology and medicine. The attempted to ensure that every chapter was written by the beautifully constructed porphyrinoid ligand, perfected over currently acknowledged expert in the ®eld, and very early on the course of evolution, provides the chromophore for a we had in our hands no less than sixty-nine signed contracts multitude of iron, magnesium, cobalt and nickel complexes for chapters. With the fullness of time, and as deadlines for which are primary metabolites and without which life itself Handbook chapter submission and other essential activities could not be maintained. (e.g., research proposal renewals) converged, some of our Falk's book, Porphyrins and Metalloporphyrins, pub- authors had to withdraw. On occasion we were able to lished in 1962, was a fairly thin volume which represented recruit new authors who, with only a month or less of lead the ®rst attempt to apply the principles of modern chemistry time, were able to ®ll these gaps and come
Hereditary Coproporphyria: Incidence in a Large English Family *

J Med Genet: first published as 10.1136/jmg.21.5.341 on 1 October 1984. Downloaded from Journal ofMedical Genetics, 1984, 21, 341-349 Hereditary coproporphyria: incidence in a large English family * J ANDREWSt, H ERDJUMENT+, AND D C NICHOLSON+ From the tDepartment of Geriatric Medicine, West Middlesex University Hospital, Isleworth, Middlesex; and ithe Department of Chemical Pathology, King's College Hospital Medical School, London SE5. SUMMARY In a family inheiiting the hereditary coproporphyria (HCP) gene, where 414 descendants have been traced through six generations and 135 members screened for faecal porphyrins, 27 subjects were found to have inherited the gene as well as the proband. Seven (six female and one male) in retrospect had probably previously suffered from a clinical attack of porphyria. Enzy- mological studies were carried out on 15 members and two unaffected parents and these results in general agreed with the faecal coproporphyrin readings. Symptomatic illness is low in HCP and is almost always precipitated by drugs known to have an adverse effect on the condition. If the gene is inherited, an attack can occur at any time between puberty and old age, such as in the proband at 84 years. We have detected abnormal faecal copro- porphyrin levels in members of this pedigree as young as 12 years and as old as 87 years. Recommendations are given concerning the necessity of tracing relatives who may have inherited the gene and arranging for their biochemical screening and genetic counselling if indicated. copyright. Dobriner1 first described the presence of excessive drug history was taken. Porphyrin estimations on the amounts of coproporphyrin isomer III in certain faeces were then carried out on the oldest surviving patients and the first clinical description was members ofeach branch of the family and, ifpositive, recorded in 1949.2 Smaller family series have been all the next generation and their progeny, if indi- reported by Haeger-Aronsen et al,3 Dean and cated, were tested.
Regulation of Heme Pathway Enzymes and Cellular Glutathione Content By

Proc. Nati. Acad. Sci. USA Vol. 74, No. 5, pp. 1875-1878, May 1977 Biochemistry Regulation of heme pathway enzymes and cellular glutathione content by metals that do not chelate with tetrapyrroles: Blockade of metal effects by thiols (metal toxicity/trace elements/cytochrome P450/renal metabolism/Ni and Pt) MAHIN D. MAINES AND ATTALLAH KAPPAS The Rockefeller University, New York, New York 10021 Communicated by E. H. Ahrens, Jr., February 11, 1977 ABSTRACT The trace metals nickel and platinum, which metals appear capable of altering heme metabolism (3) it are not substrates for ferrochelatase and thus do not form heme seemed likely that the binding of metals with such functional in biological systems, were found to act similarly to cobalt, and groups is involved in their ability to perturb cellular heme heme itself, in regulating heme metabolism in liver and kidney. These metals induced heme oxygenase activity in both organs metabolism. with the peak of induced enzyme activity reached approxi- This question was examined in the present study by utilizing mately 16 hr after single injections in rats. Both metals caused cysteine and glutathione (GSH) to increase the biological transient depression of cellular glutathione content followed availability, in animals, of binding sites for the complexing of by increases above normal after 12 hr in liver. Nickel and plat- ionic metals. The results indicate that an exogenous supply of inum were more potent inducers of heme oxygenase in kidney binding sites for metal ions can compete with endogenous than in liver (10-13 times normal versus 5-6 times normal). At regulatory binding sites for these elements and thus can render high concentrations, they inhibited heme oxygenase [heme, hydrogen-donor:oxygen oxidoreductase (a-methene-oxidizing, metals incapable of depleting cellular heme and hemoprotein.