Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:APRD00369 (ROS)
 19,271 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthesis, purification, and structural analysis of the major compounds resulting from photoderivatization of [Tyr36]-parathyroid hormone related peptide (1-36)amide [[Tyr36]PTHrP(1-36)amide] are described. The reaction of the synthetic peptide with 4-fluoro-3-nitrophenyl azide under nonaqueous conditions yields three major products (peaks D-1, D-2, and G), which were purified to homogeneity by reverse-phase high-performance liquid chromatography. Subsequent amino acid analysis showed that the peptides of peaks D-1 and G each lack one lysine residue, while the peptide in peak D-2 lacks one alanine residue, suggesting that these residues are chemically modified by photoderivatization. Sequence analysis of the photoderivatized peptides revealed that compounds D-1 and G were derivatized on Lys13 and Lys11, respectively. Compound D-2 was N-blocked, indicating that this compound is derivatized on the alpha-amino function of Ala1. Both Lys residues of D-2 were quantitatively recovered upon sequencing after digestion with endoproteinase Glu-C. Compounds D-2 and G had apparent KdS of 1 X 10(-9) M and 0.6 X 10(-9) M, respectively, for their receptors on ROS 17/2.8 cells, which are identical with or similar to that of the underivatized [Tyr36]PTHrP(1-36)amide. Compound G had the same adenylate cyclase stimulating potency as the underivatized, synthetic [Tyr36]PTHrP(1-36)amide, whereas compound D-2 was only a partial agonist, having about 25% of the maximal cAMP production. Compound D-1, which is modified on Lys13, retained only 2-4% of its receptor binding affinity and biological activity relative to that of its parent compound.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Preparation and characterization of [N alpha-(4-azido-2-nitrophenyl)Ala1,Tyr36]-parathyroid hormone related peptide (1-36)amide: a high-affinity, partial agonist having high cross-linking efficiency with its receptor on ROS 17/2.8 cells. 217 36

The synthetic bovine parathyroid hormone (PTH) analog (Nle8, Nle18, Tyr34) bovine PTH(1-34)amide (bPTH(1-34)amide) was reacted with biotinyl-epsilon aminocaproic acid-N-hydroxysuccinimide under conditions which yielded five isoforms which were fractionated by a combination of reversed phase and ion-exchange chromatography. These reaction products were analyzed by automated Edman degradation in a manner which allowed us to specify the location and number of biotin residues on picomole quantities of hormone. The ability of each of these isoforms to induce a rise in intracellular cAMP in the ROS 17/2.8 cell line allowed us to evaluate the effect on function of biotinylation at different residues. Derivatized PTH molecules which contained a single biotin at either lysine 13, lysine 26, or lysine 27 possessed full biological activity. However, bioactivity was significantly reduced when position 13 plus either lysine 26 or 27 were biotinylated. Biological activity was lost when all 3 lysine residues were biotinylated. Biotinylation of the alpha-NH2 group of alanine at the NH2 terminus also resulted in a total loss of activity. Hence, unlike the effect of altering the alanine at position 1, modification of a single lysine residue at positions 13, 26, and 27 has a less critical effect on biological activity of the molecule. However, biotinylation of all three lysines results in a biologically inert PTH derivative and suggests that changes in isoelectric point, hydrophobicity, or tertiary structure may strongly influence hormone function. A fully bioactive-mixture of isoforms was used to detect receptors on ROS 17/2.8 cells by flow cytometry using fluorescein isothiocyanate-avidin as a fluorescent indicator. Binding to cell surface receptors was saturable and could be inhibited by native bPTH(1-34) but not by transforming growth factor beta, calcitonin or insulin. Moreover, PTH receptors could also be detected on primary cultures of human bone cells and human fibroblasts.
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PMID:Biotinylated parathyroid hormone as a probe for the parathyroid hormone receptor. Structure-function analysis and detection of specific binding to cultured bone cells by flow cytometry. 255 Apr 39

The antigenicity of native DNA modified with reactive oxygen species was examined. Goats were immunized with the modified polymer and the antibody response was estimated by direct binding and competition ELISA. The induced antibodies bound ROS-DNA and showed considerable binding to native DNA as well. Specificity analysis of the purified antibodies revealed the recognition of native B-, A- and allied conformations presented by various synthetic polynucleotides. The contribution of lysine residues to the immunochemical binding of purified IgG was investigated by modifying the free amino groups of lysine residues. The modification of lysine residues paralleled loss in IgG binding to ROS-DNA to the extent of 50%, suggesting that such residues might be involved in the antigen binding site of immunoglobulin molecule.
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PMID:Antigenic specificity of anti-ROS DNA antibodies: involvement of lysyl residues in antigen binding. 753 71

Hydroxyl radical, a prominent entity of reactive oxygen species, is known to modify cellular DNA and has been implicated in several human diseases. A previously described monoclonal antibody (Mab) against reactive oxygen species-modified DNA (ROS-DNA), which preferentially recognizes ROS-modified epitopes on DNA, was used in this study. The epsilon-amino groups of lysine of the Mab were modified to study the role of these residues in Mab binding to ROS-DNA. The results demonstrate that modification of lysyl residues paralleled loss in Mab binding to ROS-DNA to the extent of 73%, suggesting the probable role of these positively charged amino acid residues in the complementarily determining regions of the Mab. The Mab was also used as an immunochemical probe to detect oxidative DNA damage in vivo in SLE. The Mab distinctly recognized five DNA samples out of eight from SLE patients and gave maximum inhibitions of 57, 58, 63, 64 and 70% in inhibition assay, while not reacting with DNA from normal, healthy population which served as negative control. High recognition of DNA isolates from SLE patients by the Mab having preferential binding to ROS-modified epitopes indicates increased oxidative stress in these patients leading to DNA damage which may contribute to the induction of antibodies cross-reacting with native DNA (nDNA).
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PMID:Detection of oxidative DNA damage by a monoclonal antibody: role of lysyl residues in antigen binding. 969 3

Amyloid beta-peptide [Abeta(1-42)] is central to the pathogenesis of Alzheimer's disease (AD), and the AD brain is under intense oxidative stress, including membrane lipid peroxidation. Abeta(1-42) causes oxidative stress in and neurotoxicity to neurons in mechanisms that are inhibited by Vitamin E and involve the single methionine residue of this peptide. In particular, Abeta induces lipid peroxidation in ways that are inhibited by free radical antioxidants. Two reactive products of lipid peroxidation are the alkenals, 4-hydroxynonenal (HNE) and 2-propenal (acrolein). These alkenals covalently bind to synaptosomal protein cysteine, histidine, and lysine residues by Michael addition to change protein conformation and function. HNE or acrolein binding to proteins introduces a carbonyl to the protein, making the protein oxidatively modified as a consequence of lipid peroxidation. Immunoprecipitation of proteins from AD and control brain, obtained no longer than 4h PMI, showed selective proteins are oxidatively modified in the AD brain. Creatine kinase (CK) and beta-actin have increased carbonyl groups, and Glt-1, a glutamate transporter, has increased binding of HNE in AD. Abeta(1-42) addition to synaptosomes also results in HNE binding to Glt-1, thereby coupling increased Abeta(1-42) in AD brain to increased lipid peroxidation and its sequelae and possibly explaining the mechanism of glutamate transport inhibition known in AD brain. Abeta also inhibits CK. Implications of these findings relate to decreased energy utilization, altered assembly of cytoskeletal proteins, and increased excitotoxicity to neurons by glutamate, all reported for AD. The epsilon-4 allele of the lipid carrier protein apolipoprotein E (APOE) allele is a risk factor for AD. Synaptosomes from APOE knock-out mice are more vulnerable to Abeta-induced oxidative stress (protein oxidation, lipid peroxidation, and ROS generation) than are those from wild-type mice. Further, synaptosomes from allele-specific APOE knock-in mice have tiered vulnerability to Abeta(1-42)-induced oxidative stress, with APOE4 more vulnerable to Abeta(1-42) than are those from APOE2 or APOE3 mice. These results are consistent with the notion of a coupling of the oxidative environment in AD brain and increased risk of developing this disorder. Taken together, the findings from in-vitro studies of lipid peroxidation induced by Abeta(1-42) and postmortem studies of lipid peroxidation (and its sequelae) in AD brain may help explain the APOE allele-related risk for AD, some of the functional and structural alterations in AD brain, and strongly support a causative role of Abeta(1-42)-induced oxidative stress in AD neurodegeneration.
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PMID:Evidence that amyloid beta-peptide-induced lipid peroxidation and its sequelae in Alzheimer's disease brain contribute to neuronal death. 1239 66

There are many examples of biologically active food proteins, with physiological significance beyond the pure nutritional requirements that concern available nitrogen for normal growth and maintenance. Moreover, there are many physiologically active peptides, derived by protease activity from various food protein sources; however, relationships between structural properties and functional activities have not been completely elucidated. Many bioactive peptides have in common structural properties that include a relatively short peptide residue length (e.g. 2-9 amino acids), possessing hydrophobic amino acid residues in addition to proline, lysine or arginine groups. Bioactive peptides are also resistant to the action of digestion peptidases. Antihypertensive peptides, known as Angiotensin I converting enzyme (ACE) inhibitors have been derived from milk, corn and fish protein sources. Peptides with opioid activities are derived from wheat gluten or casein, following digestion with pepsin. Exorphins, or opioid peptides derived from food proteins such as wheat and milk (e.g. exogenous sources) have similar structure to endogenous opioid peptides, with a tyrosine residue located at the amino terminal or bioactive site. Immunomodulatory peptides derived from tryptic hydrolysates of rice and soybean proteins act to stimulate superoxide anions (reactive oxygen species-ROS), which triggers non-specific immune defense systems. Antioxidant properties that prevent peroxidation of essential fatty acids have also been shown for peptides derived from milk proteins. The addition of a Leu or Pro residue to the N-terminus of a His-His, dipeptide will enhance antioxidant activity and facilitate further synergy with non-peptide antioxidants (e.g. BHT). We also show herein, that the tryptic digests of casein yielding caseinophosphopeptides exhibits both hydrophilic and lipophilic antioxidant activity due to both metal ion sequestering and quenching of ROS. The separation and purification of bioactive peptides which will involve development of automated and continuous systems is an important field for Food chemists. Much effort has been given to develop selective column chromatography methods that can replace batch methods of salting out, or using solvent extraction to isolate and purify bioactive peptides. Advances here will enable recovery of bioactive peptides with minimal destruction thus enabling utilization by returning these active peptides to functional food or specific nutraceutical applications.
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PMID:Bioactive proteins and peptides from food sources. Applications of bioprocesses used in isolation and recovery. 1276 39

NFkappaB is one of key transcription factors that are involved in the inflammatory responses to the particulate matter (PM) in the lungs. In order to further understand the molecular mechanism, the effects of antioxidants and an inducible nitric oxide synthase (iNOS) inhibitor on PM-induced NFkappaB activation were examined in A549 lung epithelial cells. NFkappaB activation by 2.5 microm particulates (PM2.5) was evident from the degradation of an NFkappaB inhibitory protein, IkappaBalpha, and a luciferase reporter assay for NFkappaB activity. In these experiments, a pre-treatment of the cells with antioxidants N-acetyl-l-cysteine (NAC) and dimethylthiourea (DMTU) or an iNOS inhibitor l-N6-1-iminoethyl-lysine (L-NIL) clearly inhibited the NFkappaB activation by PM2.5. The inhibitory effect of L-NIL was also observed on the PM2.5-induced interleukin-8 (IL-8) gene expression both at the transcriptional and protein levels. These results suggest that PM2.5 induces NFkappaB activity via the pathways involving ROS and/or RNS generation. Considering the fact that NFkappaB also induces NO generation via iNOS expression, they might make a positive feedback loop that amplifies the downstream responses.
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PMID:The role of nitric oxide in the particulate matter (PM2.5)-induced NFkappaB activation in lung epithelial cells. 1501 93

The combination of proteomics with highly specific and sensitive affinity techniques is important for the identification of posttranslational modifications by reactive oxygen and nitrogen species (ROS/RNS). One of the most pressing problems with this approach is to determine accurately the extent of modification of specific amino acids, such as cysteine residues, in a complex protein sample. A number of techniques relevant to free radical biology use biotin tagging as a method to follow protein modification with high sensitivity and specificity. To realize the potential of this approach to provide quantitative data, we have prepared a series of biotinylated proteins through the modification of lysine residues. These proteins were then used as quantitative standards in electrophoretic separation of protein samples labeled with biotin-conjugated iodoacetamide. The utility of the approach was assessed by measuring modification of thiols in response to exposure to thiol oxidants, as well as the amount of protein adduct formation with a biotin-tagged electrophilic lipid. Furthermore, using a combination of native and biotin-tagged cytochrome c, this method was used to quantitate the amount of thiol relative to the amount of protein in a given spot on a two-dimensional gel. Thus, we have developed a versatile, cost-effective standard that can be used in proteomic methods to quantitate biotin tags in response to oxidative stress.
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PMID:A sensitive method for the quantitative measurement of protein thiol modification in response to oxidative stress. 1644 61

Advanced glycation end products (AGEs) are elevated in aged and diabetic individuals and are associated with pathological changes associated with both. Previously we demonstrated that the AGE N(epsilon)-(carboxymethyl)lysine (CML)-collagen induced fibroblast apoptosis through the cytoplasmic and mitochondrial pathways and the global induction of proapoptotic genes. In the present study we investigated upstream mechanisms of CML-collagen-induced apoptosis. CML-collagen induced activation of the proapoptotic transcription factor FOXO1 compared with unmodified collagen. When FOXO1 was silenced, CML-collagen-stimulated apoptosis was reduced by approximately 75% compared with fibroblasts incubated with nonsilencing small interfering RNA, demonstrating the functional significance of FOXO1 activation (P < 0.05). CML-collagen but not control collagen also induced a 3.3-fold increase in p38 and a 5.6-fold increase in JNK(1/2) activity (P < 0.05). With the use of specific inhibitors, activation of p38 and JNK was shown to play an important role in CML-collagen-induced activation of FOXO1 and caspase-3. Moreover, inhibition of p38 and JNK reduced CML-collagen-stimulated apoptosis by 48 and 57%, respectively, and by 89% when used together (P < 0.05). In contrast, inhibition of the phosphatidylinositol 3-kinase/Akt pathway enhanced FOXO1 activation. p38 and JNK stimulation by CML-collagen was almost entirely blocked when formation of ROS was inhibited and was partially reduced by NO and ceramide inhibitors. These inhibitors also reduced apoptosis to a similar extent. Together these data support a model in which AGE-induced apoptosis involves the formation of ROS, NO, and ceramide and leads to p38 and JNK MAP kinase activation, which in turn induces FOXO1 and caspase-3.
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PMID:Advanced glycation end products induce apoptosis in fibroblasts through activation of ROS, MAP kinases, and the FOXO1 transcription factor. 1700 4

Previous studies have consistently shown that 40% caloric restriction (CR) decreases the rate of mitochondrial ROS production and steady-state levels of markers of oxidative damage to macromolecules including mitochondrial DNA. However, few investigations have studied whether these changes also occur in lower CR regimes. This is of potential interest since moderate levels of dietary restriction are more practicable for humans. In this investigation male Wistar rats were subjected to 8.5% and 25% caloric restriction. Neither 8.5% nor 25% CR changed mitochondrial ROS production, oxygen consumption or mtDNA oxidative damage in rat liver mitochondria. However, both 8.5% and 25% CR significantly decreased the five different markers of protein oxidation, glycoxidation and lipoxidation measured, aminoadipic and glutamic semialdehyde, carboxyethyl-lysine, carboxymethyl-lysine, and malondialdehyde-lysine. The fatty acid composition of liver mitochondria was also affected and led to a moderate decrease in the degree of membrane unsaturation in both 8.5% and 25% CR. While 8.5% CR only affected complex I concentration (which was decreased), 25% CR decreased complexes I and IV and increased complexes II and III of the respiratory chain. Apoptosis-inducing factor (AIF) significantly decreased in 25% CR but not in 8.5% CR. The results show that moderate levels of caloric restriction can have beneficial effects including decreases in oxidative protein modification and a lower sensitivity of membranes to lipid peroxidation, in association with a reprogramming of the respiratory chain complexes and AIF content.
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PMID:Effect of 8.5% and 25% caloric restriction on mitochondrial free radical production and oxidative stress in rat liver. 1748 21


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