|
Cyanophycin
Cyanophycin, also known as CGP (cyanophycin granule polypeptide) or multi-L-arginyl-poly (L-aspartic acid), is a non-protein, non-ribosomally produced amino acid polymer composed of an aspartic acid backbone and arginine side groups. Cyanophycin was first detected in 1887 by the Italian botanist ''Antonino Borzì'' and can be found in most cyanobacteria and a few heterotrophic bacteria such as ''Acinetobacter'' sp. Cyanophycin is largely insoluble under physiological conditions and is accumulated in the form of granules in the cytoplasm during phosphate or sulfur starvation, generally in the early and mid-stationary phase. It is used as a nitrogen- and possibly carbon-storage compound and also serves as a dynamic buffer for fixed nitrogen in cyanobacterial heterocysts. Nitrogen and carbon are mobilized from cyanophycin by intracellular cyanophycinase in the form of aspartate-arginine dipeptides. Cyanophycin is synthesized from arginine and aspartate in an ATP-dependent reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanophycinase
Cyanophycinase (, ''cyanophycin degrading enzyme'', ''beta-Asp-Arg hydrolysing enzyme'', ''CGPase'', ''CphB'', ''CphE'', ''cyanophycin granule polypeptidase'', ''extracellular CGPase'') is an enzyme. It catalyses the following chemical reaction : -Asp(4-L-Arg)sub>n + H2O \rightleftharpoons -Asp(4-L-Arg)sub>n-1 + L-Asp(4-L-Arg) The enzyme is highly specific for the branched polypeptide cyanophycin. It is similar to Dipeptidase E, another S51 family serine protease. Structure The asymmetric unit of cyanophycinase consists of three identical chains, each containing 291 residues. The structure of cyanophycinase was determined from the freshwater cyanobacterium Synechocystis sp. PCC 6803 at 1.5-A resolution, which showed that the structure is dimeric. Enzyme function Cyanophycinase is a carboxy terminal specific exopeptidase, meaning it catalyzes the cleavage of the carboxy terminal peptide bond of cyanophycin. It was hypothesized that cyanophycinase was a serine protease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanophycin
Cyanophycin, also known as CGP (cyanophycin granule polypeptide) or multi-L-arginyl-poly (L-aspartic acid), is a non-protein, non-ribosomally produced amino acid polymer composed of an aspartic acid backbone and arginine side groups. Cyanophycin was first detected in 1887 by the Italian botanist ''Antonino Borzì'' and can be found in most cyanobacteria and a few heterotrophic bacteria such as ''Acinetobacter'' sp. Cyanophycin is largely insoluble under physiological conditions and is accumulated in the form of granules in the cytoplasm during phosphate or sulfur starvation, generally in the early and mid-stationary phase. It is used as a nitrogen- and possibly carbon-storage compound and also serves as a dynamic buffer for fixed nitrogen in cyanobacterial heterocysts. Nitrogen and carbon are mobilized from cyanophycin by intracellular cyanophycinase in the form of aspartate-arginine dipeptides. Cyanophycin is synthesized from arginine and aspartate in an ATP-dependent reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanophycin Synthetase
Cyanophycin synthase (L-aspartate-adding) (, ''CphA'', ''CphA1'', ''CphA2'', ''cyanophycin synthetase'', ''multi-L-arginyl-poly-L-aspartate synthase'') is an enzyme with systematic name ''cyanophycin:L-aspartate ligase (ADP-forming)''. This enzyme catalyses the following chemical reaction : ATP + -Asp(4-L-Arg) + L-Asp \rightleftharpoons ADP + phosphate + -Asp(4-L-Arg)-L-Asp This enzyme requires Mg2+ for activity. All enzymes known to have this activity also catalyze the addition of arginine, i.e. cyanophycin synthase (L-arginine-adding) activity. It is structurally similar to Muramyl ligase The bacterial cell wall provides strength and rigidity to counteract internal osmotic pressure, and protection against the environment. The peptidoglycan layer gives the cell wall its strength, and helps maintain the overall shape of the cell. The ...s. References External links * {{Portal bar, Biology, border=no EC 6.3.2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonino Borzì
Antonino Borzì (20 August 1852, in Castroreale – 24 August 1921, in Lucca) was an Italian botanist. Life and career Antonino Borzì became a professor of botany at the University of Palermo in 1879 and at the University of Messina in 1892. In 1889 he was involved in reestablishing the Orto Botanico "Pietro Castelli" dell'Università di Messina. From 1892 to 1921 he was director of Orto botanico di Palermo. Antonino Borzì was the first who described the biopolymer cyanophycin Cyanophycin, also known as CGP (cyanophycin granule polypeptide) or multi-L-arginyl-poly (L-aspartic acid), is a non-protein, non-ribosomally produced amino acid polymer composed of an aspartic acid backbone and arginine side groups. Cyanophycin ... in 1887. Works (selection) * . Messina, 1883-1894 * . Palermo, 1894-1909 * . Messina, 1885 * . Messina, 1884 * . Messina, 1886 * . Palermo, 1905 * . Rome, 1911 * . 1915 * . Palermo, 1917 * . Rome, 1920 {{DEFAULTSORT:Borzi, Antonino 1852 births ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocysts
Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as ''Nostoc punctiforme'', ''Cylindrospermum stagnale'', and ''Anabaena sphaerica''. They fix nitrogen from dinitrogen (N2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis. Nitrogenase is inactivated by oxygen, so the heterocyst must create a microanaerobic environment. The heterocysts' unique structure and physiology require a global change in gene expression. For example, heterocysts: * produce three additional cell walls, including one of glycolipid that forms a hydrophobic barrier to oxygen * produce nitrogenase and other proteins involved in nitrogen fixation * degrade photosystem II, which produces oxygen * up-regulate glycolytic enzymes * produce proteins that scavenge any remaining oxygen * contain polar plugs composed of cyanophycin which slows down cell-to-ce ... [...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] |
Polyaspartic Acid
Polyaspartic acid (PASA) is a biodegradable, water-soluble condensation polymer based on the amino acid aspartic acid. It is a biodegradable replacement for water softeners and related applications. PASA can be chemically crosslinked with a wide variety of methods to yield PASA hydrogels. The resulting hydrogels are pH-sensitive such that under acidic conditions, they shrink, while the swelling capacity increases under alkaline conditions. Sodium polyaspartate is a sodium salt of polyaspartic acid. In nature, PASA has been found in as fragments of larger proteins with length up to 50 amino acids, but as of 2004 had not been isolated as a pure homo polymeric material from any natural source. The first isolation of synthetic oligomeric sodium polyaspartate, obtained by thermal polycondensation of aspartic acid, was reported by Hugo Schiff in late 19th century. Later it was proposed that thermal polymerization process leads through polysuccinimide intermediate. Polyaspartic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphoterism
In chemistry, an amphoteric compound () is a molecule or ion that can react both as an acid and as a base. What exactly this can mean depends on which definitions of acids and bases are being used. One type of amphoteric species are amphiprotic molecules, which can either donate or accept a proton (). This is what "amphoteric" means in Brønsted–Lowry acid–base theory. Examples include amino acids and proteins, which have amine () and carboxylic acid () groups, and self-ionizable compounds such as water. Ampholytes are amphoteric molecules that contain both acidic and basic functional groups. For example, an amino acid has both a basic group and an acidic group , and exists as several structures in chemical equilibrium: :H2N-RCH-CO2H + H2O H2N-RCH-COO- + H3O+ H3N+-RCH-COOH + OH- H3N+-RCH-COO- + H2O In approximately neutral aqueous solution (pH ≅ 7), the basic amino group is mostly protonated and the carboxylic acid is mostly deprotonated, so that the predominant spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corynebacterium Glutamicum
''Corynebacterium glutamicum'' is a Gram-positive, rod-shaped bacterium that is used industrially for large-scale production of amino acids. While originally identified in a screen for organisms secreting L-glutamate, mutants of ''C. glutamicum'' have also been identified that produce various other amino acids. Due to its industrial importance, several clones of ''C. glutamicum'' have been sequenced by both industry and academic groups. Furthermore, small RNA data was obtained by RNA-Seq in ''C. glutamicum'' ATCC 13032. The metabolism of this strain has been reconstructed and is available in the form of a genome-scale metabolic model. See also * List of sequenced bacterial genomes References External links Genome sequence for ''C. glutamicum''from NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the governmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Strength
Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a proton, H+, and an anion, A-. The dissociation of a strong acid in solution is effectively complete, except in its most concentrated solutions. :HA -> H+ + A- Examples of strong acids are hydrochloric acid (HCl), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). A weak acid is only partially dissociated, with both the undissociated acid and its dissociation products being present, in solution, in equilibrium with each other. :HA H+ + A- Acetic acid (CH3COOH) is an example of a weak acid. The strength of a weak acid is quantified by its acid dissociation constant, K_\ce value. The strength of a weak organic acid may depend on substituent effects. The strength of an inorganic acid is dependent on the oxidation state for the atom to which the proton may be attached. Acid strength is solvent-dependent. For example, hydrogen chloride is a strong acid in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
