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Annual Review of Nutrition Aug 2022An abundant metal in the human body, iron is essential for key biological pathways including oxygen transport, DNA metabolism, and mitochondrial function. Most iron is... (Review)
Review
An abundant metal in the human body, iron is essential for key biological pathways including oxygen transport, DNA metabolism, and mitochondrial function. Most iron is bound to heme but it can also be incorporated into iron-sulfur clusters or bind directly to proteins. Iron's capacity to cycle between Fe and Fe contributes to its biological utility but also renders it toxic in excess. Heme is an iron-containing tetrapyrrole essential for diverse biological functions including gas transport and sensing, oxidative metabolism, and xenobiotic detoxification. Like iron, heme is essential yet toxic in excess. As such, both iron and heme homeostasis are tightly regulated. Here we discuss molecular and physiologic aspects of iron and heme metabolism. We focus on dietary absorption; cellular import; utilization; and export, recycling, and elimination, emphasizing studies published in recent years. We end with a discussion on current challenges and needs in the field of iron and heme biology.
Topics: Biological Transport; Heme; Homeostasis; Humans; Iron; Mitochondria
PubMed: 35508203
DOI: 10.1146/annurev-nutr-062320-112625 -
Mini Reviews in Medicinal Chemistry 2017Thylakoids and chloroplasts harbor several vital metabolic processes, but are most importantly associated with photosynthesis. The undisturbed functioning of this... (Review)
Review
BACKGROUND & OBJECTIVE
Thylakoids and chloroplasts harbor several vital metabolic processes, but are most importantly associated with photosynthesis. The undisturbed functioning of this process necessitates the ceaseless synthesis of photosynthetic pigments, including closed tetrapyrroles such as chlorophylls (Chls). Chls probably represent the most abundant natural pigment molecules which are via photosynthesis not only crucial for the autotrophic production of food sources for heterotrophic organisms but have also contributed to oxygen production essential for aerobic metabolism. This review first briefly discusses the physico-chemical properties, biosynthesis, occurrence, in vivo localization and roles of the different Chl pigments. Then we provide a detailed overview of their potential applications in the food industry and medicine. These include the use of Chls and their derivatives (different chlorophyllins) as food colorants (identified as E140 and E141 in the European Union).
METHOD
Different sources used for industrial extraction as well as different factors influencing pigment stability during processing are also critically reviewed. The problems surrounding the nomenclature, the production and the composition of different chlorophyllin mixtures are also discussed.
RESULTS & CONCLUSION
Finally, a comprehensive overview of the health benefits and potential medicinal applications of these pigments and the future directions of research in these fields are provided.
Topics: Antineoplastic Agents; Antioxidants; Chlorophyll; Chlorophyllides; Food Coloring Agents; Humans; Neoplasms; Photochemotherapy
PubMed: 27719668
DOI: 10.2174/1389557516666161004161411 -
Current Opinion in Structural Biology Dec 2019Mechanisms for making and breaking the heme b cofactor (heme) are more diverse than previously expected. Biosynthetic pathways have diverged at least twice along... (Review)
Review
Mechanisms for making and breaking the heme b cofactor (heme) are more diverse than previously expected. Biosynthetic pathways have diverged at least twice along taxonomic lines, reflecting differences in membrane organization and O utilization among major groups of organisms. At least three families of heme degradases are now known, again differing in whether and how O is used by the organism and possibly the purpose for turning over the tetrapyrrole. Understanding these enzymes and pathways offers a handle for antimicrobial development and for monitoring heme use in organismal and ecological systems.
Topics: Binding Sites; Catalytic Domain; Heme; Metabolic Networks and Pathways; Models, Molecular; Molecular Conformation; Molecular Structure; Oxidation-Reduction; Protein Binding; Quantitative Structure-Activity Relationship; Sensitivity and Specificity
PubMed: 30802830
DOI: 10.1016/j.sbi.2019.01.006 -
Biomolecules Jul 2021Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have -, -, -, -, and -type derivatives, and all chlorophyllides have a tetrapyrrole... (Review)
Review
Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have -, -, -, -, and -type derivatives, and all chlorophyllides have a tetrapyrrole structure with a Mg ion at the center and a fifth isocyclic pentanone. Chlorophyllide can be synthesized from protochlorophyllide , divinyl chlorophyllide , or chlorophyll. In addition, chlorophyllide can be transformed into chlorophyllide , chlorophyllide , or chlorophyllide . Chlorophyllide can be synthesized from protochlorophyllide or divinyl protochlorophyllide . Chlorophyllides have been extensively used in food, medicine, and pharmaceutical applications. Furthermore, chlorophyllides exhibit many biological activities, such as anti-growth, antimicrobial, antiviral, antipathogenic, and antiproliferative activity. The photosensitivity of chlorophyllides that is applied in mercury electrodes and sensors were discussed. This article is the first detailed review dedicated specifically to chlorophyllides. Thus, this review aims to describe the definition of chlorophyllides, biosynthetic routes of chlorophyllides, purification of chlorophyllides, and applications of chlorophyllides.
Topics: Anti-Infective Agents; Antineoplastic Agents, Phytogenic; Antiviral Agents; Biosensing Techniques; Chemistry, Pharmaceutical; Chlorophyll; Chlorophyllides; Electrochemical Techniques; Food Additives; Humans; Light; Molecular Structure; Photosynthesis; Plants; Protochlorophyllide
PubMed: 34439782
DOI: 10.3390/biom11081115 -
Molecules (Basel, Switzerland) Jan 2021The covalent and noncovalent association of self-assembling peptides and tetrapyrroles was explored as a way to generate systems that mimic Nature's functional... (Review)
Review
The covalent and noncovalent association of self-assembling peptides and tetrapyrroles was explored as a way to generate systems that mimic Nature's functional supramolecular structures. Different types of peptides spontaneously assemble with porphyrins, phthalocyanines, or corroles to give long-range ordered architectures, whose structure is determined by the features of both components. The regular morphology and ordered molecular arrangement of these systems enhance the photochemical properties of embedded chromophores, allowing applications as photo-catalysts, antennas for dye-sensitized solar cells, biosensors, and agents for light-triggered therapies. Chemical modifications of peptide and tetrapyrrole structures and control over the assembly process can steer the organization and influence the properties of the resulting system. Here we provide a review of the field, focusing on the assemblies obtained from different classes of self-assembling peptides with tetrapyrroles, their morphologies and their applications as innovative functional materials.
Topics: Indoles; Isoindoles; Peptides; Photochemistry; Porphyrins; Tetrapyrroles
PubMed: 33525730
DOI: 10.3390/molecules26030693 -
International Journal of Molecular... Apr 2020Photoacoustic imaging (PAI) is a rapidly evolving field in molecular imaging that enables imaging in the depths of ultrasound and with the sensitivity of optical... (Review)
Review
Photoacoustic imaging (PAI) is a rapidly evolving field in molecular imaging that enables imaging in the depths of ultrasound and with the sensitivity of optical modalities. PAI bases on the photoexcitation of a chromophore, which converts the absorbed light into thermal energy, causing an acoustic pressure wave that can be captured with ultrasound transducers, in generating an image. For in vivo imaging, chromophores strongly absorbing in the near-infrared range (NIR; > 680 nm) are required. As tetrapyrroles have a long history in biomedical applications, novel tetrapyrroles and inspired mimics have been pursued as potentially suitable contrast agents for PAI. The goal of this review is to summarize the current state of the art in PAI applications using tetrapyrroles and related macrocycles inspired by it, highlighting those compounds exhibiting strong NIR-absorption. Furthermore, we discuss the current developments of other absorbers for in vivo photoacoustic (PA) applications.
Topics: Contrast Media; Diagnostic Imaging; Indoles; Isoindoles; Molecular Probes; Molecular Structure; Photoacoustic Techniques; Porphyrins; Tetrapyrroles
PubMed: 32349297
DOI: 10.3390/ijms21093082 -
International Journal of Molecular... Jun 2016The 18 kDa translocator protein (TSPO) is highly 0conserved in eukaryotes and prokaryotes. Since its discovery in 1977, numerous studies established the TSPO's... (Review)
Review
The 18 kDa translocator protein (TSPO) is highly 0conserved in eukaryotes and prokaryotes. Since its discovery in 1977, numerous studies established the TSPO's importance for life essential functions. For these studies, synthetic TSPO ligands typically are applied. Tetrapyrroles present endogenous ligands for the TSPO. Tetrapyrroles are also evolutionarily conserved and regulate multiple functions. TSPO and tetrapyrroles regulate each other. In animals TSPO-tetrapyrrole interactions range from effects on embryonic development to metabolism, programmed cell death, response to stress, injury and disease, and even to life span extension. In animals TSPOs are primarily located in mitochondria. In plants TSPOs are also present in plastids, the nuclear fraction, the endoplasmic reticulum, and Golgi stacks. This may contribute to translocation of tetrapyrrole intermediates across organelles' membranes. As in animals, plant TSPO binds heme and protoporphyrin IX. TSPO-tetrapyrrole interactions in plants appear to relate to development as well as stress conditions, including salt tolerance, abscisic acid-induced stress, reactive oxygen species homeostasis, and finally cell death regulation. In bacteria, TSPO is important for switching from aerobic to anaerobic metabolism, including the regulation of photosynthesis. As in mitochondria, in bacteria TSPO is located in the outer membrane. TSPO-tetrapyrrole interactions may be part of the establishment of the bacterial-eukaryote relationships, i.e., mitochondrial-eukaryote and plastid-plant endosymbiotic relationships.
Topics: Animals; Binding Sites; Biological Evolution; Biological Transport; Brain Diseases; Eukaryota; Humans; Insecta; Ligands; Plants; Prokaryotic Cells; Protein Binding; Protoporphyrins; Receptors, GABA; Structure-Activity Relationship; Tetrapyrroles
PubMed: 27271616
DOI: 10.3390/ijms17060880 -
Molecules (Basel, Switzerland) Jan 2020Natural and synthetic macrocycles like porphyrins, corroles and phthalocyanines are considered strong candidates to be used in different fields, such as catalysis,...
Natural and synthetic macrocycles like porphyrins, corroles and phthalocyanines are considered strong candidates to be used in different fields, such as catalysis, sensing, medicine, materials science, or in the development of advanced biomimetic models. All these applications are strongly dependent on the availability of compounds with adequate and specific structural features. This Special Issue has collected 13 contributions which consolidate and expand our knowledge on the application of these macrocycles in different fields accompanied by innovative synthetic methodologies to afford and to functionalize this type of compounds.
Topics: Catalysis; Macrocyclic Compounds; Photosensitizing Agents; Porphyrins; Telomerase; Tetrapyrroles
PubMed: 31972976
DOI: 10.3390/molecules25030433 -
Biochimica Et Biophysica Acta.... Jan 2021The cyclic tetrapyrrole heme is used as a prosthetic group in a broad variety of different proteins in almost all organisms. Often, it is essential for vital biochemical... (Review)
Review
The cyclic tetrapyrrole heme is used as a prosthetic group in a broad variety of different proteins in almost all organisms. Often, it is essential for vital biochemical processes such as aerobic and anaerobic respiration as well as photosynthesis. In Nature, heme is made from the common tetrapyrrole precursor 5-aminolevulinic acid, and for a long time it was assumed that heme is biosynthesized by a single, common pathway in all organisms. However, although this is indeed the case in eukaryotes, heme biosynthesis is more diverse in the prokaryotic world, where two additional pathways exist. The final elucidation of the two 'alternative' heme biosynthesis routes operating in some bacteria and archaea was achieved within the last decade. This review summarizes the three different heme biosynthesis pathways with a special emphasis on the two 'new' prokaryotic routes.
Topics: Aerobiosis; Aminolevulinic Acid; Anaerobiosis; Archaea; Bacteria; Heme; Photosynthesis; Prokaryotic Cells; Tetrapyrroles
PubMed: 32976912
DOI: 10.1016/j.bbamcr.2020.118861 -
The Journal of Biological Chemistry May 2020Modified tetrapyrroles are large macrocyclic compounds, consisting of diverse conjugation and metal chelation systems and imparting an array of colors to the biological... (Review)
Review
Modified tetrapyrroles are large macrocyclic compounds, consisting of diverse conjugation and metal chelation systems and imparting an array of colors to the biological structures that contain them. Tetrapyrroles represent some of the most complex small molecules synthesized by cells and are involved in many essential processes that are fundamental to life on Earth, including photosynthesis, respiration, and catalysis. These molecules are all derived from a common template through a series of enzyme-mediated transformations that alter the oxidation state of the macrocycle and also modify its size, its side-chain composition, and the nature of the centrally chelated metal ion. The different modified tetrapyrroles include chlorophylls, hemes, siroheme, corrins (including vitamin B), coenzyme F, heme , and bilins. After nearly a century of study, almost all of the more than 90 different enzymes that synthesize this family of compounds are now known, and expression of reconstructed operons in heterologous hosts has confirmed that most pathways are complete. Aside from the highly diverse nature of the chemical reactions catalyzed, an interesting aspect of comparative biochemistry is to see how different enzymes and even entire pathways have evolved to perform alternative chemical reactions to produce the same end products in the presence and absence of oxygen. Although there is still much to learn, our current understanding of tetrapyrrole biogenesis represents a remarkable biochemical milestone that is summarized in this review.
Topics: Pigments, Biological; Tetrapyrroles
PubMed: 32241908
DOI: 10.1074/jbc.REV120.006194