Sulfur-Sulfur Bond Isomerases
Carbon-Carbon Double Bond Isomerases
Amino Acid Isomerases
Carbon Monoxide Poisoning
Molecular Sequence Data
Fatty Acids, Unsaturated
Tacrolimus Binding Proteins
Amino Acid Sequence
Magnetic Resonance Spectroscopy
Fatty Acid Desaturases
Sequence Homology, Amino Acid
Gas Chromatography-Mass Spectrometry
Effect of the hypocholesterolemic agent YM-16638 on cholesterol biosynthesis activity and apolipoprotein B secretion in HepG2 and monkey liver. (1/145)YM-16638 ([[5-[[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propyl]thio]-1,3,4-++ +thiadiazol-2-yl] thio] acetic acid) showed a strong hypocholesterolemic effect in humans and monkeys. To clarify the mechanism of this hypocholesterolemic effect, the action of YM-16638 on cholesterol biosynthesis in the cultured human hepatoma cell line HepG2 and cynomolgus monkey liver was examined. Cholesterol biosynthesis activity derived from [14C]acetic acid, [3H/14C]mevalonic acid or [14C]isopentenyl pyrophosphate substrates was significantly decreased, but not that from [3H]farnesyl pyrophosphate or [3H]squalene substrates in HepG2 cells treated with YM-16638. Simultaneously, treatment of these cells with YM-16638 changed neither the rate of apolipoprotein B synthesis from [35S]methionine nor its secretion. In addition, the activities of hepatic cholesterol biosynthesis enzymes HMG-CoA reductase, mevalonate kinase (MK), isopentenyl pyrophosphate isomerase (IPPI), farnesyl pyrophosphate synthase (FPPS), squalene synthase and squalene epoxidase were measured in monkeys fed a diet supplemented with YM-16638. Among these enzymes, MK, IPPI and FPPS activities in the YM-16638-treated group significantly decreased by 38%, 56% and 30%, respectively, when compared to those from control animals receiving no drug treatment. These results indicate that YM-16638 has the characteristics of a cholesterol biosynthesis inhibitor. (+info)
Delta3,5,7,Delta2,4,6-trienoyl-CoA isomerase, a novel enzyme that functions in the beta-oxidation of polyunsaturated fatty acids with conjugated double bonds. (2/145)The mitochondrial metabolism of unsaturated fatty acids with conjugated double bonds at odd-numbered positions, e.g. 9-cis, 11-trans-octadecadienoic acid, was investigated. These fatty acids are substrates of beta-oxidation in isolated rat liver mitochondria and hence are expected to yield 5,7-dienoyl-CoA intermediates. 5, 7-Decadienoyl-CoA was used to study the degradation of these intermediates. After introduction of a 2-trans-double bond by acyl-CoA dehydrogenase or acyl-CoA oxidase, the resultant 2,5, 7-decatrienoyl-CoA can either continue its pass through the beta-oxidation cycle or be converted by Delta3,Delta2-enoyl-CoA isomerase to 3,5,7-decatrienoyl-CoA. The latter compound was isomerized by a novel enzyme, named Delta3,5,7,Delta2,4, 6-trienoyl-CoA isomerase, to 2,4,6-decatrienoyl-CoA, which is a substrate of 2,4-dienoyl-CoA reductase (Wang, H.-Y. and Schulz, H. (1989) Biochem. J. 264, 47-52) and hence can be completely degraded via beta-oxidation. Delta3,5,7,Delta2,4,6-Trienoyl-CoA isomerase was purified from pig heart to apparent homogeneity and found to be a component enzyme of Delta3,5,Delta2,4-dienoyl-CoA isomerase. Although the direct beta-oxidation of 2,5,7-decatrienoyl-CoA seems to be the major pathway, the degradation via 2,4,6-trienoyl-CoA makes a significant contribution to the total beta-oxidation of this intermediate. (+info)
Molecular cloning and expression of a novel human cDNA related to the diazepam binding inhibitor. (3/145)In order to isolate the unidentified autoantigens in autoimmune diabetes, a human pancreatic islet cDNA library was constructed and screened with the sera from the diabetic patients. From the library screening, one clone (DRS-1) that strongly reacted with the sera was isolated. Subsequent sequence analysis revealed that the clone was a novel cDNA related to the diazepam binding inhibitor. DRS-1 was expressed in most tissues including liver, lung, tonsil, and thymus, in addition to pancreatic islets. DRS-1 was in vitro translated and the recombinant DRS-1 protein was expressed in Escherichia coli and purified. The size of the in vitro translated or bacterially expressed DRS-1 protein was in agreement with the conceptually translated polypeptide of DRS-1 cDNA. Further studies are required to test whether or not DRS-1 is a new autoantigen in autoimmune diabetes. (+info)
Characterization of PECI, a novel monofunctional Delta(3), Delta(2)-enoyl-CoA isomerase of mammalian peroxisomes. (4/145)We report here the identification and characterization of human and mouse PECI, a novel gene that encodes a monofunctional peroxisomal Delta(3),Delta(2)-enoyl-CoA isomerase. Human and mouse PECI were identified on the basis of their sequence similarity to Eci1p, a recently characterized peroxisomal Delta(3),Delta(2)-enoyl-CoA isomerase from the yeast Saccharomyces cerevisiae. Cloning and sequencing of the human PECI cDNA revealed the presence of a 1077-base pair open reading frame predicted to encode a 359-amino acid protein with a mass of 39.6 kDa. The corresponding mouse cDNA contains a 1074-base pair open reading frame that encodes a 358-amino acid-long protein with a deduced mass of 39.4 kDa. Northern blot analysis demonstrated human PECI mRNA is expressed in all tissues. A bacterially expressed form of human PECI catalyzed the isomerization of 3-cis-octenoyl-CoA to 2-trans-octenoyl-CoA with a specific activity of 27 units/mg of protein. The human and mouse PECI proteins contain type-1 peroxisomal targeting signals, and human PECI was localized to peroxisomes by both subcellular fractionation and immunofluorescence microscopy techniques. The potential roles for this monofunctional Delta(3),Delta(2)-enoyl-CoA isomerase in peroxisomal metabolism are discussed. (+info)
Escherichia coli open reading frame 696 is idi, a nonessential gene encoding isopentenyl diphosphate isomerase. (5/145)Isopentenyl diphosphate isomerase catalyzes the interconversion of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). In eukaryotes, archaebacteria, and some bacteria, IPP is synthesized from acetyl coenzyme A by the mevalonate pathway. The subsequent isomerization of IPP to DMAPP activates the five-carbon isoprene unit for subsequent prenyl transfer reactions. In Escherichia coli, the isoprene unit is synthesized from pyruvate and glyceraldehyde-3-phosphate by the recently discovered nonmevalonate pathway. An open reading frame (ORF696) encoding a putative IPP isomerase was identified in the E. coli chromosome at 65.3 min. ORF696 was cloned into an expression vector; the 20.5 kDa recombinant protein was purified in three steps, and its identity as an IPP isomerase was established biochemically. The gene for IPP isomerase, idi, is not clustered with other known genes for enzymes in the isoprenoid pathway. E. coli FH12 was constructed by disruption of the chromosomal idi gene with the aminoglycoside 3'-phosphotransferase gene and complemented by the wild-type idi gene on plasmid pFMH33 with a temperature-sensitive origin of replication. FH12/pFMH33 was able to grow at the restrictive temperature of 44 degrees C and FH12 lacking the plasmid grew on minimal medium, thereby establishing that idi is a nonessential gene. Although the V(max) of the bacterial protein was 20-fold lower than that of its yeast counterpart, the catalytic efficiencies of the two enzymes were similar through a counterbalance in K(m)s. The E. coli protein requires Mg(2+) or Mn(2+) for activity. The enzyme contains conserved cysteine and glutamate active-site residues found in other IPP isomerases. (+info)
Rat peroxisome proliferator-activated receptors and brown adipose tissue function during cold acclimatization. (6/145)Brown adipose tissue (BAT) hyperplasia is a fundamental physiological response to cold; it involves an acute phase of mitotic cell growth followed by a prolonged differentiation phase. Peroxisome proliferator-activated receptors (PPARs) are key regulators of fatty acid metabolism and adipocyte differentiation and may therefore mediate important metabolic changes during non-shivering thermogenesis. In the present study we have investigated PPAR mRNA expression in relation to peroxisome proliferation in rat BAT during cold acclimatization. By immunoelectron microscopy we show that the number of peroxisomes per cytoplasmic volume and acyl-CoA oxidase immunolabeling density remained constant (thus increasing in parallel with tissue mass and cell number) during the initial proliferative phase and the acute thermogenic response but increased after 14 days of cold exposure, correlating with terminal differentiation of BAT. A pronounced decrease in BAT PPARalpha and PPARgamma mRNA levels was found within hours of exposure to cold, which was reversed after 14 days, suggesting a role for either or both of these subtypes in the proliferation and induction of peroxisomes and peroxisomal beta-oxidation enzymes. In contrast, PPARdelta mRNA levels increased progressively during cold exposure. Transactivation assays in HIB 1B and HEK-293 cells demonstrated an adrenergic stimulation of peroxisome proliferator response element reporter activity via PPAR, establishing a role for these nuclear receptors in hormonal regulation of gene transcription in BAT. (+info)
Alternatives to the isomerase-dependent pathway for the beta-oxidation of oleic acid are dispensable in Saccharomyces cerevisiae. Identification of YOR180c/DCI1 encoding peroxisomal delta(3,5)-delta(2,4)-dienoyl-CoA isomerase. (7/145)Fatty acids with double bonds at odd-numbered positions such as oleic acid can enter beta-oxidation via a pathway relying solely on the auxiliary enzyme Delta(3)-Delta(2)-enoyl-CoA isomerase, termed the isomerase-dependent pathway. Two novel alternative pathways have recently been postulated to exist in mammals, and these additionally depend on Delta(3,5)-Delta(2,4)-dienoyl-CoA isomerase (di-isomerase-dependent) or on Delta(3,5)-Delta(2,4)-dienoyl-CoA isomerase and 2,4-dienoyl-CoA reductase (reductase-dependent). We report the identification of the Saccharomyces cerevisiae oleic acid-inducible DCI1 (YOR180c) gene encoding peroxisomal di-isomerase. Enzyme assays conducted on soluble extracts derived from yeast cells overproducing Dci1p using 3,5,8,11,14-eicosapentenoyl-CoA as substrate demonstrated a specific di-isomerase activity of 6 nmol x min(-1) per mg of protein. Similarly enriched extracts from eci1Delta cells lacking peroxisomal 3,2-isomerase additionally contained an intrinsic 3,2-isomerase activity that could generate 3, 5,8,11,14-eicosapentenoyl-CoA from 2,5,8,11,14-eicosapentenoyl-CoA but not metabolize trans-3-hexenoyl-CoA. Amplification of this intrinsic activity replaced Eci1p since it restored growth of the eci1Delta strain on petroselinic acid for which di-isomerase is not required whereas Eci1p is. Heterologous expression in yeast of rat di-isomerase resulted in a peroxisomal protein that was enzymatically active but did not re-establish growth of the eci1Delta mutant on oleic acid. A strain devoid of Dci1p grew on oleic acid to wild-type levels, whereas one lacking both Eci1p and Dci1p grew as poorly as the eci1Delta mutant. Hence, we reasoned that yeast di-isomerase does not additionally represent a physiological 3,2-isomerase and that Dci1p and the postulated alternative pathways in which it is entrained are dispensable for degrading oleic acid. (+info)
Function of human mitochondrial 2,4-dienoyl-CoA reductase and rat monofunctional Delta3-Delta2-enoyl-CoA isomerase in beta-oxidation of unsaturated fatty acids. (8/145)Human 2,4-dienoyl-CoA reductase (2,4-reductase; DECR) and rat monofunctional Delta(3)-Delta(2)-enoyl-CoA isomerase (rat 3, 2-isomerase; ECI) are thought to be mitochondrial auxiliary enzymes involved in the beta-oxidation of unsaturated fatty acids. However, their function during this process has not been demonstrated. Although they lack obvious peroxisomal targeting signals (PTSs), both proteins have been suggested previously to also occur in the mammalian peroxisomal compartment. The putative function and peroxisomal location of the two mammalian proteins can be examined in yeast, since beta-oxidation of unsaturated fatty acids is a compartmentalized process in Saccharomyces cerevisiae requiring peroxisomal 2,4-dienoyl-CoA reductase (Sps19p) and peroxisomal 3, 2-isomerase (Eci1p). A yeast sps19Delta mutant expressing human 2, 4-reductase ending with the native C-terminus could not grow on petroselinic acid [cis-C(18:1(6))] medium but could grow when the protein was extended with a PTS tripeptide, SKL (Ser-Lys-Leu). We therefore reason that the human protein is a physiological 2, 4-reductase but that it is probably not peroxisomal. Rat 3, 2-isomerase expressed in a yeast eci1Delta strain was able to re-establish growth on oleic acid [cis-C(18:1(9))] medium irrespective of an SKL extension. Since we had shown that Delta(2,4) double bonds could not be metabolized extra-peroxisomally to restore growth of the sps19Delta strain, we postulate that rat 3,2-isomerase acted on the Delta(3) unsaturated metabolite of oleic acid by replacing the mutant's missing activity from within the peroxisomes. Immunoblotting of fractionated yeast cells expressing rat 3, 2-isomerase in combination with electron microscopy supported our proposal that the protein functioned in peroxisomes. The results presented here shed new light on the function and location of human mitochondrial 2,4-reductase and rat monofunctional 3,2-isomerase. (+info)
Carbon Monoxide Poisoning Symptoms
The symptoms of carbon monoxide poisoning can vary depending on the level and duration of exposure, but they typically include:
* Dizziness or nausea
* Slurred speech
* Loss of consciousness
In severe cases, carbon monoxide poisoning can cause brain damage, coma, and even death.
Carbon Monoxide Poisoning Causes
Carbon monoxide is a byproduct of incomplete combustion of fuels such as gasoline, natural gas, or wood. Sources of carbon monoxide poisoning include:
* Faulty heating systems or water heaters
* Poorly vented appliances like stoves and fireplaces
* Clogged chimneys or vents
* Running cars in enclosed spaces like garages
* Overcrowding with too many people in a small, poorly ventilated space
Diagnosis of Carbon Monoxide Poisoning
Doctors may suspect carbon monoxide poisoning based on symptoms and medical history. Blood tests can measure the level of carboxyhemoglobin (COHb) in red blood cells, which indicates CO exposure. Chest X-rays or CT scans may also be used to check for signs of lung damage.
Treatment of Carbon Monoxide Poisoning
The treatment of carbon monoxide poisoning involves moving the patient to a location with fresh air and administering oxygen therapy to help remove CO from the bloodstream. In severe cases, medication may be given to help stimulate breathing and improve oxygenation of tissues. Hyperbaric oxygen therapy may also be used in some cases.
Prevention of Carbon Monoxide Poisoning
Prevention is key when it comes to carbon monoxide poisoning. Some steps you can take to prevent CO poisoning include:
* Installing a carbon monoxide detector in your home
* Regularly inspecting and maintaining appliances like furnaces, water heaters, and chimneys
* Properly venting appliances and ensuring they are installed in well-ventilated areas
* Not running cars or generators in enclosed spaces
* Avoiding overcrowding and ensuring there is adequate ventilation in living spaces
Carbon monoxide poisoning is a serious condition that can be fatal if not treated promptly. It's important to be aware of the sources of CO exposure and take steps to prevent it, such as installing carbon monoxide detectors and regularly maintaining appliances. If you suspect CO poisoning, seek medical attention immediately.
The symptoms of carbon tetrachloride poisoning can vary depending on the level and duration of exposure, but may include:
* Respiratory problems, such as coughing, wheezing, and shortness of breath
* Nausea and vomiting
* Abdominal pain and diarrhea
* Headaches and dizziness
* Confusion and disorientation
* Slurred speech and loss of coordination
* Seizures and coma
If you suspect that you or someone else has been exposed to carbon tetrachloride, it is essential to seek medical attention immediately. Treatment for carbon tetrachloride poisoning typically involves supportive care, such as oxygen therapy and hydration, as well as medications to manage symptoms and remove the toxin from the body. In severe cases, hospitalization may be necessary.
Prevention is key when it comes to carbon tetrachloride poisoning. If you work with or are exposed to CTC, it is important to take safety precautions such as wearing protective clothing and equipment, using proper ventilation, and following all safety protocols. It is also essential to handle the chemical with care and store it in a safe location.
In conclusion, carbon tetrachloride poisoning can be a serious and potentially deadly condition that requires immediate medical attention. If you suspect exposure to CTC, it is crucial to seek medical help right away. By taking safety precautions and being aware of the risks associated with this chemical, you can prevent carbon tetrachloride poisoning and protect your health.
List of MeSH codes (D08)
Enoyl CoA isomerase
2,4 Dienoyl-CoA reductase
List of types of proteins
Isopentenyl-diphosphate delta isomerase
Photoactive yellow protein
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- 12. Site-directed mutagenesis of putative active-site amino acid residues of 3,2-trans-enoyl-CoA isomerase, conserved within the low-homology isomerase/hydratase enzyme family. (nih.gov)
- Does the isomerase enzyme RPE65 operate via nucleophilic addition at C(11) of the all-trans substrate, or via a carbocation mechanism? (nih.gov)
- Covalent attachment via an isopeptide bond to its substrates requires prior activation by the E1 complex SAE1-SAE2 and linkage to the E2 enzyme UBE2I, and can be promoted by an E3 ligase such as PIAS1-4, RANBP2 or CBX4. (nih.gov)
- The enzyme functions by hydrolyzing glycosidic bonds in peptidoglycans . (cloudfront.net)
- The enzyme can also break glycosidic bonds in chitin , although not as effectively as true chitinases . (cloudfront.net)
- The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds. (lookformedical.com)
- Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties. (lookformedical.com)
- Twenty-carbon polyunsaturated fatty acid with cyclopentane ring. (medscape.com)
- Enzymes that catalyze the shifting of a carbon-carbon double bond from one position to another within the same molecule. (nih.gov)
- Subcellular distribution of delta 3,delta 2-enoyl-CoA isomerase activity in rat liver. (nih.gov)
- Two decades later, the prostaglandins were deduced to be a family of related compounds that contain 20-carbon polyunsaturated fatty acids with a cyclopentane ring, as depicted below. (medscape.com)