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Pullulanase
Pullulanase (, ''limit dextrinase'', ''amylopectin 6-glucanohydrolase'', ''bacterial debranching enzyme'', ''debranching enzyme'', ''alpha-dextrin endo-1,6-alpha-glucosidase'', ''R-enzyme'', ''pullulan alpha-1,6-glucanohydrolase'') is a specific kind of glucanase, an amylolytic exoenzyme, that degrades pullulan. It is produced as an extracellular, cell surface-anchored lipoprotein by Gram-negative bacteria of the genus ''Klebsiella''. Type I pullulanases specifically attack α-1,6 linkages, while type II pullulanases are also able to hydrolyse α-1,4 linkages. It is also produced by some other bacteria and archaea. Pullulanase is used as a processing aid in grain processing biotechnology (production of ethanol and sweeteners). Pullulanase is also known as pullulan-6-glucanohydrolase (Debranching enzyme). Its substrate, pullulan, is regarded as a chain of maltotriose units linked by alpha-1,6-glycosidic bond A glycosidic bond or glycosidic linkage is a type of covalent bond that j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucanase
Glucanases are enzymes that break down large polysaccharides via hydrolysis. The product of the hydrolysis reaction is called a glucan, a linear polysaccharide made of up to 1200 glucose monomers, held together with glycosidic bonds. Glucans are abundant in the endosperm cell walls of cereals such as barley, rye, sorghum, rice, and wheat. Glucanases are also referred to as lichenases, hydrolases, glycosidases, glycosyl hydrolases, and/or laminarinases. Many types of glucanases share similar amino acid sequences but vastly different substrates. Of the known endo-glucanases, 1,3-1,4-β-glucanase is considered the most active. Structure β-glucanases The secondary and tertiary structures of β-glucanases involves the stacking of multiple β-sheets, each of which are made of several anti-parallel strands that bend and form a cleft crossing the active site of the enzyme. This type of structure has been called the "jelly roll fold." Some common β-glucanases * 1,3-β-glucana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoenzyme
An exoenzyme, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside that cell. Exoenzymes are produced by both prokaryotic and eukaryotic cells and have been shown to be a crucial component of many biological processes. Most often these enzymes are involved in the breakdown of larger macromolecules. The breakdown of these larger macromolecules is critical for allowing their constituents to pass through the cell membrane and enter into the cell. For humans and other complex organisms, this process is best characterized by the digestive system which breaks down solid food via exoenzymes. The small molecules, generated by the exoenzyme activity, enter into cells and are utilized for various cellular functions. Bacteria and fungi also produce exoenzymes to digest nutrients in their environment, and these organisms can be used to conduct laboratory assays to identify the presence and function of such exoenzymes. Some pathogenic species also use ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pullulan
Pullulan is a polysaccharide polymer consisting of maltotriose units, also known as α-1,4- ;α-1,6-glucan'. Three glucose units in maltotriose are connected by an α-1,4 glycosidic bond, whereas consecutive maltotriose units are connected to each other by an α-1,6 glycosidic bond. Pullulan is produced from starch by the fungus ''Aureobasidium pullulans''. Pullulan is mainly used by the cell to resist desiccation and predation. The presence of this polysaccharide also facilitates diffusion of molecules both into and out of the cell. As an edible, mostly tasteless polymer, the chief commercial use of pullulan is in the manufacture of edible films that are used in various breath freshener or oral hygiene products such as Listerine Cool Mint of Johnson and Johnson (USA) and Meltz Super Thin Mints of Avery Bio-Tech Private Ltd. (India). Pullulan and HPMC can also be used as a vegetarian substitute for drug capsules, rather than gelatine. As a food additive, it is known by the E num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoprotein
A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward toward the surrounding water and lipophilic portions oriented inward toward the lipid center. A special kind of protein, called apolipoprotein, is embedded in the outer shell, both stabilising the complex and giving it a functional identity that determines its role. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins. Examples include plasma lipoprotein particles ( HDL, LDL, IDL, VLDL and chylomicrons). Subgroups of these plasma particles are primary drivers or modulators of atherosclerosis. Scope Transmembrane lipoproteins Some transmembrane proteolipids, especially those found in bacteria, are referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', '' Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klebsiella
''Klebsiella'' is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. ''Klebsiella'' species are found everywhere in nature. This is thought to be due to distinct sublineages developing specific niche adaptations, with associated biochemical adaptations which make them better suited to a particular environment. They can be found in water, soil, plants, insects and other animals including humans. ''Klebsiella'' is named after German-Swiss microbiologist Edwin Klebs (1834–1913). Carl Friedlander described ''Klebsiella'' bacillus which is why it was termed Friedlander bacillus for many years. The members of the genus ''Klebsiella'' are a part of the human and animal's normal flora in the nose, mouth and intestines. The species of ''Klebsiella'' are all gram-negative and usually non-motile. They tend to be shorter and thicker when compared to others in the family Enterobacteriaceae. The cells are rods in shape and general ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biotechnology
Biotechnology is the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. The term ''biotechnology'' was first used by Károly Ereky in 1919, meaning the production of products from raw materials with the aid of living organisms. Definition The concept of biotechnology encompasses a wide range of procedures for modifying living organisms according to human purposes, going back to domestication of animals, cultivation of the plants, and "improvements" to these through breeding programs that employ artificial selection and hybridization. Modern usage also includes genetic engineering as well as cell and tissue culture technologies. The American Chemical Society defines biotechnology as the application of biological organisms, systems, or processes by various industries to learning about the science of life and the improvement of the value of materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a hydroxyl group). Ethanol is a Volatility (chemistry), volatile, Combustibility and flammability, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, the active ingredient in alcoholic drinks. Ethanol is naturally produced by the fermentation process of Carbohydrate, sugars by yeasts or via Petrochemistry, petrochemical processes such as ethylene hydration. It has medical applications as an antiseptic and disinfectant. It is used as a chemical solvent and in the Chemical synthesis, synthesis of organic compounds, and as a Alcohol fuel, fuel source. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2006, world produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosidic Bond
A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside. The term 'glycoside' is now extended to also cover compounds with bonds formed between hemiacetal (or hemiketal) groups of sugars and several chemical groups other than hydroxyls, such as -SR (thioglycosides), -SeR (selenoglycosides), -NR1R2 (N-glycosides), or even -CR1R2R3 (C-glycosides). Particularly in naturally occurring glycosides, the compound ROH from which the carbohydrate residue has been removed is often termed the aglycone, and the carbohydrate residue itself is sometimes referred to as the 'glycone'. S-, N-, C-, and O-glycosidic bonds Glycosidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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