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Peroxisomal Disorders
A peroxisome () is a membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells. Peroxisomes are oxidative organelles. Frequently, molecular oxygen serves as a co-substrate, from which hydrogen peroxide (H2O2) is then formed. Peroxisomes owe their name to hydrogen peroxide-generating and scavenging activities. They perform key roles in lipid metabolism and the reduction of reactive oxygen species. Peroxisomes are involved in the catabolism of very long chain fatty acids, branched chain fatty acids, bile acid intermediates (in the liver), D-amino acids, and polyamines. Peroxisomes also play a role in the biosynthesis of plasmalogens: ether phospholipids critical for the normal function of mammalian brains and lungs. Peroxisomes contain approximately 10% of the total activity of two enzymes (Glucose-6-phosphate dehydrogenase and 6-Phosphogluconate dehydrogenase) in the pentose phosphate pathway, which is important for energy meta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmalogen
Plasmalogens are a class of glycerophospholipid with a plasmenyl group linked to a lipid at the sn-1 position of the glycerol backbone. Plasmalogens are found in multiple domains of life, including Mammal, mammals, Invertebrate, invertebrates, protozoa, and Anaerobic organism, anaerobic bacteria. They are commonly found in cell membranes in the nervous system, nervous, immune system, immune, and cardiovascular systems. In humans, lower levels of plasmalogens are studied in relation to some diseases. Plasmalogens are also associated with adaptations to extreme environments in non-human organisms. Structure Glycerophospholipids of biochemical relevance are divided into three subclasses based on the substitution present at the Glycerophospholipid#Nomenclature and stereochemistry, sn-1 position of the glycerol backbone: acyl_group, acyl, alkyl_group, alkyl and alkenyl_group, alkenyl. Of these, the alkyl and alkenyl moiety in each case form an ether bond, which makes for two types o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a light, Volatility (chemistry), volatile, colorless and flammable liquid with a distinctive alcoholic odor similar to that of ethanol (potable alcohol), but is more acutely toxic than the latter. Methanol acquired the name wood alcohol because it was once produced through destructive distillation of wood. Today, methanol is mainly produced industrially by hydrogenation of carbon monoxide. Methanol consists of a methyl group linked to a polar hydroxyl group. With more than 20 million tons produced annually, it is used as a Precursor (chemistry), precursor to other commodity chemicals, including formaldehyde, acetic acid, methyl tert-butyl ether, methyl ''tert''-butyl ether, methyl benzoate, anisole, peroxyacids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosome
The glycosome is a membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...-enclosed organelle that contains the glycolysis, glycolytic enzymes. The term was first used by Scott and Still in 1968 after they realized that the glycogen in the cell was not static but rather a dynamic molecule. It is found in a few species of protozoa including the Kinetoplastida which include the suborders Trypanosomatida and Bodonina, most notably in the human pathogenic trypanosomes, which can cause African trypanosomiasis, sleeping sickness, Chagas's disease, and leishmaniasis. The organelle is bounded by a single membrane and contains a dense proteinaceous matrix. It is believed to have evolved from the peroxisome. This has been verified by work done on Leishmania genetics. The glycosome is curre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypanosomes
Trypanosomatida is a group of kinetoplastid unicellular organisms distinguished by having only a single flagellum. The name is derived from the Greek language, Greek ''trypano'' (borer) and ''soma'' (body) because of the corkscrew-like motion of some trypanosomatid species. All members are exclusively parasite, parasitic, found primarily in insects. A few genera have life-cycles involving a secondary host, which may be a vertebrate, invertebrate or plant. These include several species that cause major diseases in humans. Some trypanosomatida are intracellular parasites, with the important exception of ''Trypanosoma brucei''. Medical importance The three major human diseases caused by trypanosomatids are; African trypanosomiasis (African trypanosomiasis, sleeping sickness, caused by ''Trypanosoma brucei'' and transmitted by Tsetse fly, tsetse flies), South American trypanosomiasis (Chagas disease, caused by ''Trypanosoma cruzi, T. cruzi'' and transmitted by Triatominae, triatomi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycolysis
Glycolysis is the metabolic pathway that converts glucose () into pyruvic acid, pyruvate and, in most organisms, occurs in the liquid part of cells (the cytosol). The Thermodynamic free energy, free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and NADH, reduced nicotinamide adenine dinucleotide (NADH). Glycolysis is a sequence of ten reactions catalyzed by enzymes. The wide occurrence of glycolysis in other species indicates that it is an ancient metabolic pathway. Indeed, the reactions that make up glycolysis and its parallel pathway, the pentose phosphate pathway, can occur in the Great Oxygenation Event, oxygen-free conditions of the Archean oceans, also in the absence of enzymes, catalyzed by metal ions, meaning this is a plausible prebiotic pathway for abiogenesis. The most common type of glycolysis is the ''Embden–Meyerhof–Parnas (EMP) pathway'', which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Kar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photorespiration
Photorespiration (also known as the oxidative photosynthetic carbon cycle or C2 cycle) refers to a process in plant physiology, plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis. The desired reaction is the addition of carbon dioxide to RuBP (carboxylation), a key step in the Calvin–Benson cycle, but approximately 25% of reactions by RuBisCO instead add oxygen to RuBP (Oxygenase, oxygenation), creating a product that cannot be used within the Calvin–Benson cycle. This process lowers the efficiency of photosynthesis, potentially lowering photosynthetic output by 25% in C3 carbon fixation, plants. Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria. The oxygenation reaction of RuBisCO is a wasteful process because 3-Phosphoglyceric acid, 3-phosphoglycerate is created at a lower rate and higher metabolic cost compared wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyoxysomes
Glyoxysomes are specialized peroxisomes found in plants (particularly in the fat storage tissues of germinating seeds) and also in filamentous fungi. Seeds that contain fats and oils include corn, soybean, sunflower, peanut and pumpkin. As in all peroxisomes, in glyoxysomes the fatty acids are oxidized to acetyl-CoA by peroxisomal β-oxidation enzymes. When the fatty acids are oxidized hydrogen peroxide (H2O2) is produced as oxygen (O2) is consumed. Thus the seeds need oxygen to germinate. Besides peroxisomal functions, glyoxysomes possess additionally the key enzymes of the glyoxylate cycle ( isocitrate lyase and malate synthase) which accomplish the glyoxylate cycle bypass. Thus, glyoxysomes (as all peroxisomes) contain enzymes that initiate the breakdown of fatty acids and additionally possess the enzymes to produce intermediate products for the synthesis of sugars by gluconeogenesis. The seedling uses these sugars synthesized from fats until it is mature enough to prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyoxylate Cycle
The glyoxylate cycle, a variation of the tricarboxylic acid cycle, is an anabolic pathway occurring in plants, bacteria, protists, and fungi. The glyoxylate cycle centers on the conversion of acetyl-CoA to succinate for the synthesis of carbohydrates. In microorganisms, the glyoxylate cycle allows cells to use two carbons (C2 compounds), such as acetate, to satisfy cellular carbon requirements when simple sugars such as glucose or fructose are not available. The cycle is generally assumed to be absent in animals, with the exception of nematodes at the early stages of embryogenesis. In recent years, however, the detection of malate synthase (MS) and isocitrate lyase (ICL), key enzymes involved in the glyoxylate cycle, in some animal tissue has raised questions regarding the evolutionary relationship of enzymes in bacteria and animals and suggests that animals encode alternative enzymes of the cycle that differ in function from known MS and ICL in non-metazoan species. Plants as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesterol
Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all animal Cell (biology)#Eukaryotic cells, cells and is an essential structural and cholesterol signaling, signaling component of animal cell membranes. In vertebrates, hepatocyte, hepatic cells typically produce the greatest amounts. In the brain, astrocytes produce cholesterol and transport it to neurons. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as ''Mycoplasma'', which require cholesterol for growth. Cholesterol also serves as a Precursor (chemistry), precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Elevated levels of cholesterol in the blood, especially when bound to low-density lipoprotein (LDL, often referred to as "bad cholesterol"), may increase the risk of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoprenoid
The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes", terpenoids contain additional functional groups, usually containing oxygen. When combined with the hydrocarbon terpenes, terpenoids comprise about 80,000 compounds. They are the largest class of plant secondary metabolites, representing about 60% of known natural products. Many terpenoids have substantial pharmacological bioactivity and are therefore of interest to medicinal chemists. Plant terpenoids are used for their aromatic qualities and play a role in traditional herbal remedies. Terpenoids contribute to the scent of eucalyptus, the flavors of cinnamon, cloves, and ginger, the yellow color in sunflowers, and the red color in tomatoes. Well-known terpenoids include citral, menthol, camphor, salvinorin A in the plant '' S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentose Phosphate Pathway
The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt or HMP shunt) is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses (five-carbon sugars) as well as ribose 5-phosphate, a precursor for the synthesis of nucleotides. While the pentose phosphate pathway does involve oxidation of glucose, its primary role is anabolic rather than catabolic. The pathway is especially important in red blood cells (erythrocytes). The reactions of the pathway were elucidated in the early 1950s by Bernard Horecker and co-workers. There are two distinct phases in the pathway. The first is the oxidative phase, in which NADPH is generated, and the second is the non-oxidative synthesis of five-carbon sugars. For most organisms, the pentose phosphate pathway takes place in the cytosol; in plants, most steps take place in plastids. Like glycolysis, the pentose phosphate pathway appears to have a very ancient evolutionary ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
