RESUMEN
Supercapacitors (SCs), including electric double-layer capacitors (EDLCs), pseudocapacitors, and hybrid capacitors, are esteemed for their high power density and attractive features such as robust safety, fast charging, low maintenance, and prolonged cycling lifespan, sparking significant interest. Carbon quantum dots (CQDs) are fluorescent nanomaterials with small size, broad excitation spectrum, stable fluorescence, and adjustable emission wavelengths. They are widely used in optoelectronics, medical diagnostics, and energy storage due to their biocompatibility, low toxicity, rich surface functional groups, abundant electron-hole pairs, large specific surface area, and tunable heteroatom doping. In this short review, we briefly discussed the advantages and disadvantages of bottom-up and top-down of CQD synthesis methods. The arc-discharge technique, laser ablation technique, plasma treatment, ultrasound synthesis technique, electrochemical technique, chemical exfoliation, and combustion are among the initial top-down approaches. The subsequent section delineates waste-derived and bottom-up methods, encompassing microwave synthesis, hydrothermal synthesis, thermal pyrolysis, and the metal-organic framework template-assisted technique. In addition, this short review focuses on the operational mechanism of supercapacitors, their properties, and the utilization of CQDs in supercapacitors.
RESUMEN
For enhanced applications of solar cells, organic luminescence materials like long persistent luminescence (LPL) present one of the promising avenues for light enhancement. Currently, most existing luminescent materials are based on an inorganic system that requires rare elements such as europium and dysprosium, with a very high processing temperature. Adopting organic luminescence materials that are free from rare elements is necessary, considering the low-temperature fabrication and low material cost. In this work, we investigate the optical properties of an organic luminescence blend consisting of 2,8-bis(diphenylphosphoryl)dibenzo [b,d]thiophene (PPT) and N,N,N',N'-tetramethylbenzidine (TMB) through computational studies and experimental validations. Optical characteristics of the luminescence materials like optical absorption, photoluminescence, and time-resolved photoluminescence spectroscopy are characterized. To validate the functionality of the organic luminescence blend, the material is incorporated into the perovskite solar cell structure. Unfortunately, the blend is unable to emit sufficient illumination over extended periods due to its low intersystem crossing efficiency and weak spin-orbit coupling. Although the power conversion efficiency of the Luminescence/FTO/TiO2/Perovskite/Carbon structure is observed to be small under dark conditions, the application of organic luminescence materials can be further enhanced and explored.
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Tannerella forsythia is a major periodontal pathogen, and T. forsythia GroEL is a molecular chaperone homologous to human heat-shock protein 60. Interleukin-17 (IL-17) has been implicated in the pathogenesis of periodontitis and several systemic diseases. This study investigated the potential of T. forsythia GroEL to induce inflammatory bone resorption and examined the cooperative effect of IL-17 and T. forsythia GroEL on inflammatory responses. Human gingival fibroblasts (HGFs) and periodontal ligament (PDL) fibroblasts were stimulated with T. forsythia GroEL and/or IL-17. Gene expression of IL-6, IL-8, and cyclooxygenase-2 (COX-2) and concentrations of IL-6, IL-8, and prostaglandin E2 (PGE2 ) were measured by real-time reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assays, respectively. After stimulation of MG63 cells with T. forsythia GroEL and/or IL-17, gene expression of osteoprotegerin (OPG) was examined. After subcutaneous injection of T. forsythia GroEL and/or IL-17 above the calvaria of BALB/c mice, calvarial bone resorption was assessed by micro-computed tomography and histological examination. Tannerella forsythia GroEL induced IL-6 and IL-8 production in HGFs and PDL cells, and IL-17 further promoted IL-6 and IL-8 production. Both T. forsythia GroEL and IL-17 synergistically increased PGE2 production and inhibited OPG gene expression. Calvarial bone resorption was induced by T. forsythia GroEL injection, and simultaneous injection of T. forsythia GroEL and IL-17 further increased bone resorption. These results suggest that T. forsythia GroEL is a novel virulence factor that can contribute to inflammatory bone resorption caused by T. forsythia and synergizes with IL-17 to exacerbate inflammation and bone resorption.
Asunto(s)
Resorción Ósea/microbiología , Chaperonina 60/metabolismo , Inflamación , Interleucina-17/inmunología , Tannerella forsythia/inmunología , Tannerella forsythia/patogenicidad , Animales , Resorción Ósea/inmunología , Resorción Ósea/patología , Chaperonina 60/farmacología , Ciclooxigenasa 2/genética , Ciclooxigenasa 2/metabolismo , Dinoprostona/genética , Dinoprostona/inmunología , Ensayo de Inmunoadsorción Enzimática , Fibroblastos/microbiología , Encía/citología , Encía/inmunología , Encía/microbiología , Interleucina-1/genética , Interleucina-1/inmunología , Interleucina-17/farmacología , Interleucina-6/genética , Interleucina-6/inmunología , Interleucina-8/genética , Interleucina-8/inmunología , Ratones , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Periodontitis/inmunología , Cráneo/inmunología , Cráneo/patología , Factores de Virulencia , Microtomografía por Rayos XRESUMEN
Although enolases are cytosolic enzymes involved in the glycolytic pathway, they can also be secreted or expressed on the surface of a variety of eukaryotic cells and bacteria. Surface-exposed enolases of eukaryotes and bacteria can function as plasminogen receptors. Furthermore, antibodies raised against bacterial enolases can react with host enolases, suggesting molecular mimicry between bacterial and host enzymes. In this study, we analyzed an enolase of the major periodontopathogen Tannerella forsythia, which is either secreted or present on the cell surface, via matrix-assisted laser desorption ionization time-of-flight mass spectrometry and immunofluorescence, respectively. The T. forsythia enolase retained the enzymatic activity converting 2-phosphoglycerate to phosphoenolpyruvate and showed plasminogen binding and activating ability, which resulted in the degradation of fibronectin secreted from human gingival fibroblasts. In addition, it induced proinflammatory cytokine production, including interleukin-1ß (IL-1ß), IL-6, IL-8, and tumour necrosis factor-α (TNF-a) in the human THP-1 monocytic cell line. Taken together, our results demonstrate that T. forsythia enolase plays a role in pathogenesis in the host by plasminogen activation and proinflammatory cytokine induction, which has the potential to exaggerate inflammation in periodontitis.
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Fosfopiruvato Hidratasa/metabolismo , Tannerella forsythia/enzimología , Tannerella forsythia/patogenicidad , Proteínas Bacterianas/metabolismo , Proteínas Portadoras/metabolismo , Línea Celular , Células Cultivadas , Citocinas/biosíntesis , Activación Enzimática , Ensayo de Inmunoadsorción Enzimática , Fibroblastos/metabolismo , Encía/metabolismo , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Mediadores de Inflamación/metabolismo , Interleucinas/biosíntesis , Interleucinas/inmunología , Monocitos , Periodontitis/metabolismo , Periodontitis/microbiología , Fosfopiruvato Hidratasa/genética , Fosfopiruvato Hidratasa/inmunología , Plasminógeno/análisis , Tannerella forsythia/genética , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
In the pathogenesis of periodontitis, Porphyromonas gingivalis plays a role as a keystone pathogen that manipulates host immune responses leading to dysbiotic oral microbial communities. Arg-gingipains (RgpA and RgpB) and Lys-gingipain (Kgp) are responsible for the majority of bacterial proteolytic activity and play essential roles in bacterial virulence. Therefore, gingipains are often considered as therapeutic targets. This study investigated the role of gingipains in the modulation by P. gingivalis of phagocytosis of Tannerella forsythia by macrophages. Phagocytosis of T. forsythia was significantly enhanced by coinfection with P. gingivalis in a multiplicity of infection-dependent and gingipain-dependent manner. Mutation of either Kgp or Rgp in the coinfecting P. gingivalis resulted in attenuated enhancement of T. forsythia phagocytosis. Inhibition of coaggregation between the two bacterial species reduced phagocytosis of T. forsythia in mixed infection, and this coaggregation was dependent on gingipains. Inhibition of gingipain protease activities in coinfecting P. gingivalis abated the coaggregation and the enhancement of T. forsythia phagocytosis. However, the direct effect of protease activities of gingipains on T. forsythia seemed to be minimal. Although most of the phagocytosed T. forsythia were cleared in infected macrophages, more T. forsythia remained in cells coinfected with gingipain-expressing P. gingivalis than in cells coinfected with the gingipain-null mutant or infected only with T. forsythia at 24 and 48 h post-infection. Collectively, these results suggest that P. gingivalis, mainly via its gingipains, alters the clearance of T. forsythia, and provide some insights into the role of P. gingivalis as a keystone pathogen.
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Adhesinas Bacterianas/inmunología , Cisteína Endopeptidasas/inmunología , Macrófagos/microbiología , Fagocitosis , Porphyromonas gingivalis/inmunología , Tannerella forsythia/inmunología , Adhesinas Bacterianas/genética , Línea Celular , Técnicas de Cocultivo , Cisteína Endopeptidasas/genética , Cisteína-Endopeptidasas Gingipaínas , Humanos , Macrófagos/inmunología , Macrófagos/ultraestructura , Microscopía Confocal , Mutación , Periodontitis/inmunología , Periodontitis/microbiología , Porphyromonas gingivalis/patogenicidadRESUMEN
OBJECTIVE: The aim of this study was to evaluate the effects of Tannerella forsythia and its major surface virulence factor, BspA, on the progression of atherosclerosis in ApoE(-/-) mice and the expression of lipid metabolism-related genes. METHODS: PMA-differentiated THP-1 cells were treated with BspA to detect foam cell formation. The proximal aortas of ApoE(-/-) mice injected with T. forsythia or BspA were stained with oil red O to examine lipid deposition. The serum levels of CRP, HDL, and LDL were detected by ELISA. The liver tissue of T. forsythia- or BspA-injected ApoE(-/-) mice was examined for mRNA expression of lipid metabolism-related genes, such as liver X receptors (LXRα and LXRß) and ATP-binding cassette transporter A1 (ABCA1). RESULTS: Tannerella forsythia and BspA induced foam cell formation in THP-1 cells and accelerated the progression of atherosclerotic lesions in ApoE(-/-) mice. Mouse serum levels of CRP and LDL were increased, and HDL was decreased by T. forsythia and BspA. The expression levels of LXRα and LXRß, and ABCA1 in liver tissue were decreased by T. forsythia and BspA. CONCLUSIONS: Tannerella forsythia and BspA augmented atherosclerotic lesion progression in ApoE(-/-) mice. This process may be associated with downregulation of lipid metabolism-related gene expression.
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Apolipoproteínas E/genética , Aterosclerosis/metabolismo , Proteínas Bacterianas/fisiología , Proteínas de la Membrana/fisiología , Porphyromonas/metabolismo , Animales , Aterosclerosis/genética , Aterosclerosis/microbiología , Aterosclerosis/patología , Línea Celular , Progresión de la Enfermedad , Humanos , Hígado/metabolismo , Ratones , Ratones Noqueados , Factores de RiesgoRESUMEN
Infection and inflammation are risk factors in the initiation and progression of atherosclerosis. Periodontitis is one of the most prevalent chronic inflammations of the oral cavity, and has been reported to be associated with systemic disease. In this study, we evaluated whether the heat-shock protein GroEL of Fusobacterium nucleatum, one of the most prevalent bacteria in periodontitis, induces factors that predispose to atherosclerosis in human microvascular endothelial cells (HMEC-1) and apolipoprotein E-deficient (ApoE(-/-)) mice. GroEL induced the expression of chemokines such as monocyte chemoattractant protein-1 and interleukin-8 as well as cell adhesion molecules, such as intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin. GroEL induced the activity of tissue factor and reduced the activity of the tissue factor pathway inhibitor. Foam cell formation was induced by GroEL. GroEL-injected ApoE(-/-) mice showed significant atherosclerotic lesion progression compared with control mice. Serum levels of risk factors for atherosclerosis such as interleukin-6, C-reactive protein, and low-density lipoprotein were increased in GroEL-injected ApoE(-/-) mice compared with control mice, whereas serum levels of high-density lipoprotein were decreased. We could detect significantly higher levels of anti-F. nucleatum GroEL antibody in serum and F. nucleatum DNA in gingival crevicular fluid from patients with periodontitis than in that from healthy subjects. Our results indicate that the host response to the GroEL of periodontal pathogens like F. nucleatum may be a mechanism involved in atherosclerosis, supporting the association of periodontitis and systemic infection.
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Aterosclerosis/etiología , Chaperonina 60/fisiología , Periodontitis Crónica/microbiología , Endotelio Vascular/citología , Fusobacterium nucleatum/metabolismo , Animales , Anticuerpos Antibacterianos/sangre , Apolipoproteínas E/deficiencia , Moléculas de Adhesión Celular/biosíntesis , Células Cultivadas , Quimiocinas/biosíntesis , Clonación Molecular , Placa Dental/microbiología , Células Espumosas , Humanos , Lipoproteínas/fisiología , Masculino , Ratones , Ratones Noqueados , Monocitos/fisiología , Proteínas Recombinantes/farmacología , Factores de Riesgo , Tromboplastina/biosíntesis , Tromboplastina/fisiologíaRESUMEN
Fusobacterium nucleatum plays a pivotal role in dental plaque biofilm formation and is known to be involved in chronic inflammatory systemic disease. However, limited knowledge of F. nucleatum genes expressed in vivo interferes with our understanding of pathogenesis. In this study, we identified F. nucleatum genes induced in vivo using in-vivo-induced antigen technology (IVIAT). Among 30,000 recombinant clones screened, 87 reacted reproducibly with pooled sera from 10 patients with periodontitis. The clones encoded for 32 different proteins, of which 28 could be assigned to their functions, which were categorized in translation, transcription, transport, energy metabolism, cell envelope, cellular process, fatty acid and phospholipid metabolism, transposition, cofactor biosynthesis, amino acid biosynthesis, and DNA replication. Putative virulence factors detected were ABC transporter, butyrate-acetoacetate CoA-transferase, hemin receptor, hemolysin, hemolysin-related protein, LysR family transcriptional regulator, serine protease, and transposase. Analysis of immune responses to the in-vivo-induced (ivi) antigens in five patients demonstrated that most were reactive to these proteins, confirming results with pooled sera. IVIAT-identified F. nucleatum genes in this study may accelerate the elucidation of F. nucleatum-mediated molecular pathogenesis.
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Epítopos , Infecciones por Fusobacterium/inmunología , Fusobacterium nucleatum/genética , Genes Bacterianos/genética , Transportadoras de Casetes de Unión a ATP/genética , Antígenos Bacterianos/sangre , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Técnicas Bacteriológicas , Transporte Biológico/genética , Línea Celular , Pared Celular/ultraestructura , Coenzima A Transferasas/genética , Metabolismo Energético/genética , Células Epiteliales/inmunología , Células Epiteliales/microbiología , Epítopos/inmunología , Fusobacterium nucleatum/clasificación , Fusobacterium nucleatum/inmunología , Regulación Bacteriana de la Expresión Génica/genética , Proteínas Hemolisinas/genética , Humanos , Metabolismo de los Lípidos/genética , Periodontitis/sangre , Periodontitis/microbiología , Biosíntesis de Proteínas/genética , Serina Proteasas/genética , Factores de Transcripción/genética , Transcripción Genética/genética , Transposasas/genética , Factores de Virulencia/genéticaRESUMEN
BACKGROUND AND OBJECTIVE: Periodontitis is a chronic inflammatory disease of the periodontium that causes significant alveolar bone loss. Osteoclasts are bone-resorbing multinucleated cells. Osteoblasts regulate osteoclast differentiation by expression of RANKL and osteoprotegerin (OPG). Td92 is a surface-exposed outer membrane protein of Treponema denticola, a periodontopathogen. Although it has been demonstrated that Td92 acts as a stimulator of various proinflammatory mediators, the role of Td92 in alveolar bone resorption remains unclear. Therefore, in this study, we investigated the role of Td92 in bone resorption. MATERIAL AND METHODS: Mouse bone marrow cells were co-cultured with calvariae-derived osteoblasts in the presence or absence of Td92. Osteoclast formation was assessed by TRAP staining. Expressions of RANKL, osteoprotegerin (OPG) and prostaglandin E(2) (PGE(2) ) in osteoblasts were estimated by ELISA. RESULTS: Td92 induced osteoclast formation in the co-cultures. In the osteoblasts, RANKL and PGE(2) expressions were up-regulated, whereas OPG expression was down-regulated by Td92. The addition of OPG inhibited Td92-induced osteoclast formation. The prostaglandin synthesis inhibitors NS398 and indomethacin were also shown to inhibit Td92-induced osteoclast formation. The effects of Td92 on the expressions of RANKL, OPG and PGE(2) in osteoblasts were blocked by NS398 or indomethacin. CONCLUSION: These results suggest that Td92 promotes osteoclast formation through the regulation of RANKL and OPG production via a PGE(2) -dependent mechanism.
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Adhesinas Bacterianas/fisiología , Pérdida de Hueso Alveolar/metabolismo , Dinoprostona/metabolismo , Osteoclastos/fisiología , Osteoprotegerina/biosíntesis , Ligando RANK/biosíntesis , Treponema denticola/química , Adhesinas Bacterianas/genética , Adhesinas Bacterianas/farmacología , Pérdida de Hueso Alveolar/microbiología , Animales , Células de la Médula Ósea , Células Cultivadas , Técnicas de Cocultivo , Regulación de la Expresión Génica , Ratones , Ratones Endogámicos , Osteoblastos , Osteoclastos/efectos de los fármacos , Osteoclastos/metabolismo , Osteoprotegerina/genética , Ligando RANK/genética , Proteínas Recombinantes/farmacología , Treponema denticola/fisiologíaRESUMEN
Several features of the implant surface, such as roughness, topography and composition play a relevant role in implant integration with bone. This study was conducted in order to determine the effects of various thin layer hydroxyapatite (HA) coatings on anodized Ti surfaces on the biological responses of a human osteoblast-like cell line (MG63). MG63 cells were cultured on 100 nm HA (100 nm HA coating on anodized surface), 500-700 nm HA (500-700 nm HA coating on anodized surface), 1 mum HA (1 mum HA coating on anodized surface) and anodize (non-HA coating on anodized surface) Ti. The morphology of these cells was assessed by scanning electron microscopy (SEM). The cDNAs prepared from the total RNAs of the MG63 were hybridized into a human cDNA microarray (1152 elements). The appearances of the surfaces observed by SEM were different on each of the four dental substrate types. MG63 cells cultured on 100 nm HA, 1 mum HA and anodize exhibited cell-matrix interactions. It was 500-700 nm HA surface showing cell-cell interaction. In the expression of genes involved in osseointegration, several genes, including bone morphogenetic protein 2, latent transforming growth factor beta binding protein 1, catenin (cadherin-associated protein), integrin, PDGFRB and GDF-1 growth differentiation factor 1 were up-regulated on the different surfaces. Several genes, including fibroblast growth factor receptor 3, fibroblast growth factor 12 and CD4 were down-regulated on the different surfaces. The attachment and expression of key osteogenic regulatory genes were enhanced by the surface morphology of the dental materials used.
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Materiales Biocompatibles Revestidos/farmacología , Implantes Dentales , Durapatita/farmacología , Osteoblastos/efectos de los fármacos , Titanio/química , Supervivencia Celular/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Humanos , Ensayo de Materiales/métodos , Microscopía Electrónica de Rastreo , Oseointegración/genética , Osteoblastos/ultraestructura , Propiedades de SuperficieRESUMEN
The vmc gene encoding a metalloprotease of Vibrio mimicus (ATCC 33653) was cloned in Escherichia coli and sequenced. The vmc gene contained 1884 nt sequence which codes a polypeptide of 628 amino acids with a predicted molecular mass of 71,275 Da. The deduced amino acid sequence had the similarity of 68.5% with V. parahaemolyticus metalloprotease. The consensus sequence of a zinc binding motif (HEXXH) was identified to be HEYTH. The zymography analysis showed a gelatinolytic protein band around molecular mass of 61 kDa, and this result suggested that the cloned metalloprotease may undergo processing during secretion.
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Proteínas Bacterianas/genética , Genes Bacterianos , Metaloendopeptidasas/genética , Vibrio/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Datos de Secuencia Molecular , Alineación de Secuencia , Análisis de SecuenciaRESUMEN
The genetic diversity of hepatitis G virus (HGV) was investigated. By using a RT-PCR procedure, 14% of either HBV (hepatitis B virus)- or HCV (hepatitis C virus)-positive Korean hepatitis patients were proved to be HGV positives. Nucleotide sequences in the E1 region of the eight isolates from Korean patients and the six previously reported isolates were compared. Nucleotide substitutions spread uniformly throughout the E1 region. Sequence homology among the Korean isolates was 84-99% and 88-99% at the nucleotide and amino acid sequences, respectively, whereas those from different geographic areas was slightly lower at both levels. At least two genotypes might exist among the Korean HGV isolates. Compared to the corresponding region of HCV, the E1 sequence from HGV is moderately conserved. In addition, as frameshift mutations were observed in most of the Korean isolates compared to the prototype HGV sequence, the Korean isolates might not use the translational initiation site of the prototype HGV for polyprotein translation. Because a putative signal sequence of E1 for entry into endoplasmic reticulum starts from the N-terminus of the polyprotein, and capsid-like peptides composed of basic amino acids could not be detected from the upstream region of E1, the core protein of HGV is absent, or at least not present, at the region next to 5'-UTR. Therefore, HGV could be clearly distinguished from other genera of Flaviviridae.
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Flaviviridae/genética , Productos del Gen env/genética , Genes env , Hepatitis Viral Humana/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Flaviviridae/aislamiento & purificación , Productos del Gen env/química , Productos del Gen env/aislamiento & purificación , Hepatitis Viral Humana/virología , Humanos , Corea (Geográfico) , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , ARN Viral/aislamiento & purificación , Análisis de Secuencia de ARNRESUMEN
An extracellular adenosine deaminase was isolated from the culture supernatant of Nocardioides sp. J-326TK and purified 193-fold to homogeneity. It had a specific activity of 4677 units/mg at 37 degrees C, was a monomeric protein as judged by SDS/PAGE, and was characterized with respect to M(r) (80,000 and 72,000 by gel filtration on Sephadex G-200 and SDS/PAGE respectively), pH optimum (6.0), temperature optimum (50 degrees C) and pI (7.6). The adsorption spectrum of the enzyme had a maximum at 280 nm and a minimum at 250 nm. The enzyme was stable at pH 6.5-7.5 and at temperatures below 30 degrees C. Adenosine and 2'-deoxyadenosine were deaminated and the respective Km values were 0.22 and 0.20 mM, but the enzyme was not active on adenine and 6-(gamma gamma'-dimethylallylamino)purine riboside. The enzyme reaction was promoted by Fe3+ and Sn2+, but potently inhibited by Hg2+, Ag2+, o-phenanthroline and pentachlorophenol, and noticeably inhibited by 8-bromoadenosine, theobromine and theophylline.
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Adenosina Desaminasa/aislamiento & purificación , Isoenzimas/aislamiento & purificación , Nocardiaceae/enzimología , Adenosina Desaminasa/biosíntesis , Adenosina Desaminasa/efectos de los fármacos , Medios de Cultivo , Estabilidad de Enzimas , Concentración de Iones de Hidrógeno , Isoenzimas/biosíntesis , Isoenzimas/efectos de los fármacos , Metales/farmacología , Peso Molecular , Nucleósidos/química , Espectrofotometría Ultravioleta , Especificidad por Sustrato , TemperaturaRESUMEN
Hemoprotein derivatives of an abundant soybean (Glycine max Merr.) root nodule leghemoglobin, Lba, were studied for their modified spectral characteristics and physical properties. Three modified hemoprotein derivatives of Lba (Lbam1, Lbam2, and Lbam3) were purified by preparative isoelectric focusing. The ferric forms of these pigments were green and exhibited anomalous spectra in the visible region as compared to the Lba3+ forms. These modified pigments showed a hypochromic shift of 10 nm for the charge transfer absorption maximum; however, differences were not apparent in the Soret region. Upon binding with nicotinate, the [alpha] and [beta] bands were shifted significantly into the red region as compared to the Lba3+ nicotinate complex. The three Lbam fractions were reduced by dithionite or by NADH in the presence of riboflavin. Lbam2+ also bound nicotinate and displayed absorption spectra indistinguishable from those of Lba2+ nicotinate. In contrast to Lba2+, Lbam2+ displayed aberrant spectra when bound with either O2 or CO. These complexes exhibited a prominent charge transfer band at approximately 620 nm and failed to exhibit spectra characteristic of Lba2+O2 and Lba2+CO. The protein moiety of these modified pigments was intact because their tyrosine/tryptophan ratios and their amino acid compositions were identical with those of Lba, nor were differences observed in the peptide profiles resulting from trypsin digests of purified Lba and Lbams. Automated Edman degradation of selected peaks further confirmed the intactness of the protein backbone including the absence of deamination. Pyridine hemochromogen for heme from Lbams could be formed, and the spectra displayed distinct differences compared to those of Lba. A new peak at 580 nm and a loss of a peak at 480 nm were observed for all three Lbams.