Journal ArticleDOI
Protoporphyrin IX-induced structural and functional changes in human red blood cells, haemoglobin and myoglobin.
TLDR
Spectrophotometric studies reveal that protoporphyrin IX interacts with haemoglobin and myoglobin forming ground state complexes, which may have a role in establishing efficacy of therapeutic uses of porphyrins as well as in elucidating their mechanisms of action as therapeutic agents.Abstract:
Protoporphyrin IX and its derivatives are used as photosensitizers in the photodynamic therapy of cancer. Protoporphyrin IX penetrates into human red blood cells and releases oxygen from them. This leads to a change in the morphology of the cells. Spectrophotometric studies reveal that protoporphyrin IX interacts with haemoglobin and myoglobin forming ground state complexes. For both proteins, the binding affinity constant decreases, while the possible number of binding sites increases, as the aggregation state of the porphyrin is increased. The interactions lead to conformational changes of both haemoglobin and myoglobin as observed in circular dichroism studies. Upon binding with the proteins, protoporphyrin IX releases the heme-bound oxygen from the oxyproteins, which is dependent on the stoichiometric ratios of the porphyrin : protein. The peroxidase activities of haemoglobin and myoglobin are potentiated by the protein-porphyrin complexation. Possible mechanisms underlying the relation between the porphyrin-induced structural modifications of the heme proteins and alterations in their functional properties have been discussed. The findings may have a role in establishing efficacy of therapeutic uses of porphyrins as well as in elucidating their mechanisms of action as therapeutic agents.read more
Citations
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Heme cytotoxicity and the pathogenesis of immune-mediated inflammatory diseases.
TL;DR: Targeting “free heme” may be used as a therapeutic intervention against diseases related to oxidative stress and immune-mediated inflammatory conditions.
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Characterization of a Mycobacterium tuberculosis Nanocompartment and Its Potential Cargo Proteins
Heidi Contreras,Matthew S. Joens,Lisa M. McMath,Vincent P. Le,Michael V. Tullius,Jacqueline M. Kimmey,Neda Bionghi,Marcus A. Horwitz,James A. J. Fitzpatrick,Celia W. Goulding +9 more
TL;DR: It is shown by co-purification and electron microscopy that mycobacteria via Mt-Enc can encapsulate Mt-DyP, Mt-BfrB, and Mt-FolB, which may aid in detoxification of the local environment to ensure long term survival.
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Pulmonary Proteases in the Cystic Fibrosis Lung Induce Interleukin 8 Expression from Bronchial Epithelial Cells via a Heme/Meprin/Epidermal Growth Factor Receptor/Toll-like Receptor Pathway
TL;DR: It is shown that the Pseudomonas proteases and the neutrophil proteases (neutrophil elastase (NE) and proteinase-3) are capable of almost complete degradation of hemoglobin in vitro but that NE is the predominant protease that cleaves hemoglobinIn vivo in CF bronchoalveolar lavage fluid.
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Role of the c-Jun N-terminal kinase signaling pathway in SW480 cell apoptosis in response to 5-aminolevulinic acid-based photodynamic therapy
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Enhancement techniques for improving 5-aminolevulinic acid delivery through the skin
TL;DR: Enhanced delivery systems for ALA in the skin will play an important role in ALA-PDT, and several enhancement techniques for increasing ALA permeation through the skin are introduced.
References
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Journal ArticleDOI
Conformational changes induced in bovine serum albumin by the photodynamic action of haematoporphyrin.
TL;DR: The photodynamic action of haematoporphyrin upon bovine serum albumin, spin-labelled at the cysteine-34 residue, has been shown to increase its susceptibility to proteolysis by chymotrypsin and trypsin, and increaseIts susceptibility to denaturation by urea.
Journal ArticleDOI
Impairment of red cell membrane cytoskeleton by protoporphyrin‐ix: light and dark effects
N. Dadosh,N. Shaklai +1 more
TL;DR: It was concluded that illumination in the presence of porphyrin causes membrane rigidity by crosslinking of the cytoskeletal proteins, and their sensitivity to crossl linking is the result of their mutual arrangement in the membrane.
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Folding and unfolding of δ-aminolevulinic acid dehydratase and porphobilinogen deaminase induced by uro- and protoporphyrin
TL;DR: It is suggested that porphyrins per se can act directly on protein structure and that this action may be enhanced by UV irradiation.
Journal ArticleDOI
Trifluoperazine is more effective than chlorpromazine in releasing oxygen from haemoglobin and myoglobin.
TL;DR: The extent of oxygen release from two heme proteins, haemoglobin and myoglobin, have been studied in the presence of trifluoperazine and chlorpromazine (5–1000 μM).
Journal ArticleDOI
Hematoporphyrin interacts with myoglobin and alters its functions
TL;DR: The binding parameters of hematoporphyrin, a photosensitizing drug used in photodynamic therapy, interacting with myoglobin, an oxygen storage protein, have been studied spectrofluorometrically and spectrophotometric.