Bioactivity of [6R]-5-formyltetrahydrofolate, an unnatural isomer, in humans and Enterococcus hirae, and cytochrome c oxidation of 10-formyltetrahydrofolate to 10-formyldihydrofolate

2001 ◽  
Vol 354 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Joseph E. BAGGOTT ◽  
Constance B. ROBINSON ◽  
Kelly E. JOHNSTON
Keyword(s):  
Cytochrome C ◽  
Rate Constant ◽  
Oxidation Reaction ◽  
Control Medium ◽  
Enterococcus Hirae ◽  
Naturally Occurring ◽  
Cyt C ◽  
Exogenous Source ◽  
Large Rate Constant

The bio-inactive C-6 isomer, [6R]-5-formyl-tetrahydrofolate (5-HCO-H4F), is not found in Nature. An oral dose of 13.5µmol of [6R]-5-HCO-H4F in humans results in the appearance of the naturally occurring [6S]-5-methyl-tetrahydrofolate and relatively large amounts of other bioactive folates in plasma. The removal of the asymmetry at C-6 could account for these results. Two oxidized cytochrome c [cyt c (Fe3+)] molecules oxidize one 10-formyl-tetrahydrofolate (10-HCO-H4F) with second-order kinetics and a rate constant of 1.3×;104 M-1·s-1. The folate product of this oxidation reaction is 10-formyl-dihydrofolate (10-HCO-H2F), which has no C-6 asymmetric centre and is therefore bioactive. The folate-requiring bacterium, Enterococcus hirae, does not normally biosynthesize cytochromes but does so when given an exogenous source of haem (e.g. haemin). E. hirae grown in haemin-supplemented media for 3 days utilizes both [6R]- and [6S]-5-HCO-H4F in contrast to that grown in control medium, which utilizes only the [6S] isomer. Since known chemical reactions form 10-HCO-H4F from 5-HCO-H4F, the unusually large rate constant for the oxidation of 10-HCO-H4F by cyt c (Fe3+) may account for the unexpected bioactivity of [6R]-5-HCO-H4F in humans and in E. hirae grown in haemin-containing media. We used an unnatural C-6 folate isomer as a tool to reveal the possible in vivo oxidation of 10-HCO-H4F to 10-HCO-H2F; however, nothing precludes this oxidation from occurring in vivo with the natural C-6 isomer.

Differences in renal metabolism of insulin and cytochrome c

1988 ◽  
Vol 254 (4) ◽  
pp. E419-E428 ◽  
Author(s):  
J. Herrman ◽  
R. E. Simmons ◽  
B. H. Frank ◽  
R. Rabkin
Keyword(s):  
Cytochrome C ◽  
Lysosomal Enzyme ◽  
Subcellular Distribution ◽  
Sucrose Gradient ◽  
Insulin Degradation ◽  
Renal Metabolism ◽  
Small Proteins ◽  
Cyt C ◽  
Alternate Routes

Kidneys degrade small proteins such as cytochrome c (CYT c) by the classic lysosomal pathway. However, because alternate routes for the transport and degradation of protein hormones have been identified in other tissues, we set out to determine whether extralysosomal sites might participate in the renal degradation of insulin. First, we compared the effect of the lysosomal inhibitor NH4Cl on insulin and CYT c degradation by isolated perfused rat kidneys. After kidneys were loaded with radiolabeled proteins to allow for absorption and transport to lysosomes, degradation was measured in the presence or absence of inhibitors. Control kidneys degraded 45 +/- 1.5% of the trapped CYT c per hour, and this was inhibited 62 +/- 1.3% by NH4Cl. In contrast, 86 +/- 2.4% of the trapped insulin was degraded per hour, and this was inhibited 26 +/- 4% by NH4Cl. Next we followed the subcellular distribution of 125I-labeled insulin in kidneys exposed to 125I-labeled insulin in vivo or when isolated and perfused. Under both circumstances the distribution of insulin on a linear sucrose gradient differed from that of the lysosomal enzyme N-acetyl-beta-glucosaminidase. In contrast, [14CH3]CYT c, injected in vivo, distributed over a density similar to the lysosomal marker. Thus important differences exist between the renal metabolism of CYT c, which proceeds in lysosomes, and the renal metabolism of insulin. These include rate of degradation, sensitivity to NH4Cl, and subcellular sites of localization. Accordingly, we suggest that insulin degradation may occur, at least in part, in a different compartment from the classic lysosomal site of protein degradation.

scholarly journals Optimization and Characterization of Protein Nanoparticles for the Targeted and Smart Delivery of Cytochrome c to Non-Small Cell Lung Carcinoma

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1215
Author(s):  
Vanessa Barcelo-Bovea ◽  
Irivette Dominguez-Martinez ◽  
Freisa Joaquin-Ovalle ◽  
Luis A. Amador ◽  
Elizabeth Castro-Rivera ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Delivery System ◽  
Lung Carcinoma ◽  
Near Infrared ◽  
Small Cell Lung Carcinoma ◽  
In Vivo Studies ◽  
Cell Lung Carcinoma ◽  
Cyt C ◽  
Poly Ethylene

The delivery of Cytochrome c (Cyt c) to the cytosol stimulates apoptosis in cells where its release from mitochondria and apoptotic induction is inhibited. We developed a drug delivery system consisting of Cyt c nanoparticles decorated with folate-poly(ethylene glycol)-poly(lactic-co-glycolic acid)-thiol (FA-PEG-PLGA-SH) to deliver Cyt c into cancer cells and tested their targeting in the Lewis Lung Carcinoma (LLC) mouse model. Cyt c-PLGA-PEG-FA nanoparticles (NPs) of 253 ± 55 and 354 ± 11 nm were obtained by Cyt c nanoprecipitation, followed by surface decoration with the co-polymer SH-PLGA-PEG-FA. The internalization of Cyt c-PLGA-PEG-FA nanoparticles (NPs) in LLC cells was confirmed by confocal microscopy. NP caspase activation was more efficient than the NP-free formulation. Caspase activity assays showed NPs retained 88–96% Cyt c activity. The NP formulations were more effective in decreasing LLC cell viability than NP-free formulation, with IC50 49.2 to 70.1 μg/mL versus 129.5 μg/mL, respectively. Our NP system proved to be thrice as selective towards cancerous than normal cells. In vivo studies using near infrared-tagged nanoparticles show accumulation in mouse LLC tumor 5 min post-injection. In conclusion, our NP delivery system for Cyt c shows superiority over the NP-free formulation and reaches a folic acid-overexpressing tumor in an immune-competent animal model.

scholarly journals Optimization and Characterization of Protein Nanoparticles for the Targeted and Smart Delivery of Cytochrome c to Non-Small Cell Lung Carcinoma

2020 ◽  
Author(s):  
Vanessa Barcelo-Bovea ◽  
Irivette Dominguez-Martinez ◽  
Freisa Joaquin-Ovalle ◽  
Luis A. Amador ◽  
Elizabeth Castro-Rivera ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Delivery System ◽  
Lung Carcinoma ◽  
Small Cell Lung Carcinoma ◽  
In Vivo Studies ◽  
Cell Lung Carcinoma ◽  
Cyt C ◽  
Surface Decoration ◽  
Poly Ethylene

The delivery of Cytochrome c (Cyt c) to the cytosol stimulates apoptosis in cells were its release from mitochondria and apoptosis induction is inhibited. We developed a drug delivery system consisting of Cyt c nanoparticles decorated with folate-poly(ethylene glycol)-poly(lactic-co-glycolic acid)-thiol (FA-PEG-PLGA-SH) to deliver Cyt c into cancer cells and test their targeting in the Lewis Lung Carcinoma (LLC) mouse model. Cyt c-PLGA-PEG-FA nanoparticles (NPs) of 253 ± 55 and 354 ± 11 nm were obtained by Cyt c nanoprecipitation, followed by surface decoration with the co-polymer SH-PLGA-PEG-FA, and compared to a nanoparticle-free formulation. Overexpression of FA in LLC cells and internalization of Cyt c-PLGA-PEG-FA nanoparticles (NPs) was confirmed by confocal microscopy. Caspase activation assays show NPs retain 88-96% Cyt c activity. The NP formulations were more efficient in decreasing LLC cell viability than the NP-free formulation, with IC50: 49.2 to 70.1 μg/ml versus 129.5 μg/ml, respectively. Our NP system is thrice as selective towards cancerous than normal cells. In-vivo studies using tagged nanoparticles show accumulation in mouse LLC tumor 5 min post-injection. In conclusion, our NP delivery system for Cyt c shows superiority over the NP-free formulation and reaches a folic acid-overexpressing tumor in an immune-competent animal model.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

scholarly journals Conifers Phytochemicals: A Valuable Forest with Therapeutic Potential

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 3005
Author(s):  
Kanchan Bhardwaj ◽  
Ana Sanches Silva ◽  
Maria Atanassova ◽  
Rohit Sharma ◽  
Eugenie Nepovimova ◽  
...  
Keyword(s):  
Experimental Data ◽  
Potential Role ◽  
Therapeutic Potential ◽  
Fungal Infections ◽  
Cell Damage ◽  
Cancer Growth ◽  
Naturally Occurring ◽  
Antioxidant Effects

Conifers have long been recognized for their therapeutic potential in different disorders. Alkaloids, terpenes and polyphenols are the most abundant naturally occurring phytochemicals in these plants. Here, we provide an overview of the phytochemistry and related commercial products obtained from conifers. The pharmacological actions of different phytochemicals present in conifers against bacterial and fungal infections, cancer, diabetes and cardiovascular diseases are also reviewed. Data obtained from experimental and clinical studies performed to date clearly underline that such compounds exert promising antioxidant effects, being able to inhibit cell damage, cancer growth, inflammation and the onset of neurodegenerative diseases. Therefore, an attempt has been made with the intent to highlight the importance of conifer-derived extracts for pharmacological purposes, with the support of relevant in vitro and in vivo experimental data. In short, this review comprehends the information published to date related to conifers’ phytochemicals and illustrates their potential role as drugs.

scholarly journals Cytochrome c Deficiency Differentially Affects the In Vivo Mitochondrial Electron Partitioning and Primary Metabolism Depending on the Photoperiod

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 444
Author(s):  
Igor Florez-Sarasa ◽  
Elina Welchen ◽  
Sofia Racca ◽  
Daniel H. Gonzalez ◽  
José G. Vallarino ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Tca Cycle ◽  
Day Length ◽  
Primary Metabolism ◽  
Stress Signaling ◽  
Alternative Pathways ◽  
Tca Cycle Intermediates ◽  
Growth Adaptation ◽  
Plant Respiration

Plant respiration provides metabolic flexibility under changing environmental conditions by modulating the activity of the nonphosphorylating alternative pathways from the mitochondrial electron transport chain, which bypass the main energy-producing components of the cytochrome oxidase pathway (COP). While adjustments in leaf primary metabolism induced by changes in day length are well studied, possible differences in the in vivo contribution of the COP and the alternative oxidase pathway (AOP) between different photoperiods remain unknown. In our study, in vivo electron partitioning between AOP and COP and expression analysis of respiratory components, photosynthesis, and the levels of primary metabolites were studied in leaves of wild-type (WT) plants and cytochrome c (CYTc) mutants, with reduced levels of COP components, under short- and long-day photoperiods. Our results clearly show that differences in AOP and COP in vivo activities between WT and cytc mutants depend on the photoperiod likely due to energy and stress signaling constraints. Parallel responses observed between in vivo respiratory activities, TCA cycle intermediates, amino acids, and stress signaling metabolites indicate the coordination of different pathways of primary metabolism to support growth adaptation under different photoperiods.

scholarly journals Regulation of Cytochrome c Oxidase by Natural Compounds Resveratrol, (–)-Epicatechin, and Betaine

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1346
Author(s):  
Icksoo Lee
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Model Systems ◽  
Health Improvement ◽  
Published Data ◽  
Mitochondrial Electron Transport Chain ◽  
Naturally Occurring ◽  
Transport Chain ◽  
Wide Range ◽  
Experimental Model Systems

Numerous naturally occurring molecules have been studied for their beneficial health effects. Many compounds have received considerable attention for their potential medical uses. Among them, several substances have been found to improve mitochondrial function. This review focuses on resveratrol, (–)-epicatechin, and betaine and summarizes the published data pertaining to their effects on cytochrome c oxidase (COX) which is the terminal enzyme of the mitochondrial electron transport chain and is considered to play an important role in the regulation of mitochondrial respiration. In a variety of experimental model systems, these compounds have been shown to improve mitochondrial biogenesis in addition to increased COX amount and/or its enzymatic activity. Given that they are inexpensive, safe in a wide range of concentrations, and effectively improve mitochondrial and COX function, these compounds could be attractive enough for possible therapeutic or health improvement strategies.

scholarly journals Regulation of rat magnocellular neurosecretory system by D-aspartate: evidence for biological role(s) of a naturally occurring free D-amino acid in mammals

2000 ◽  
Vol 167 (2) ◽  
pp. 247-252 ◽  
Author(s):  
H Wang ◽  
H Wolosker ◽  
J Pevsner ◽  
SH Snyder ◽  
DJ Selkoe
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Amino Acid ◽  
Physiological Function ◽  
Neurosecretory System ◽  
Milk Ejection ◽  
Magnocellular Neurons ◽  
Rat Hypothalamus ◽  
Naturally Occurring

Little evidence is available for the physiological function of D-amino acids in species other than bacteria. Here we demonstrate that naturally occurring freed -aspartate (D-Asp) is present in all magnocellular neurons of rat hypothalamus. The levels of this naturally occurring D-amino acid were elevated during lactation and returned to normal thereafter in the magnocellular neurosecretory system, which produces oxytocin, a hormone responsible for milk ejection during lactation. Intraperitoneal injections of D-Asp reproducibly increased oxytocin gene expression and decreased the concentration of circulating oxytocin in vivo. Similar changes were observed in the vasopressin system. These results provide evidence for the role(s) of naturally occurring free D-Asp in mammalian physiology. The findings argue against the conventional concept that only L-stereoisomers of amino acids are functional in higher species.

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