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Phosphagen
Phosphagens, also known as macroergic compounds, are high energy storage compounds, also known as high-energy phosphate compounds, chiefly found in muscular tissue in animals. They allow a high-energy phosphate pool to be maintained in a concentration range, which, if it all were adenosine triphosphate (ATP), would create problems due to the ATP-consuming reactions in these tissues. As muscle tissues can have sudden demands for much energy, these compounds can maintain a reserve of high-energy phosphates that can be used as needed, to provide the energy that could not be immediately supplied by glycolysis or oxidative phosphorylation. Phosphagens supply immediate but limited energy. The actual biomolecule used as a phosphagen is dependent on the organism. The majority of animals use arginine as phosphagen; however, the phylum Chordata (i.e., animals with spinal cords) use creatine. Creatine phosphate (CP), or phosphocreatine (PCr), is made from ATP by the enzyme creatine kinase in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATP-PC
Bioenergetic systems are metabolic processes that relate to the flow of energy in living organisms. Those processes convert energy into adenosine triphosphate (ATP), which is the form suitable for muscular activity. There are two main forms of synthesis of ATP: ''aerobic'', which uses oxygen from the bloodstream, and ''anaerobic'', which does not. Bioenergetics is the field of biology that studies bioenergetic systems. Overview The process that converts the chemical energy of food into ATP (which can release energy) is not dependent on oxygen availability. During exercise, the supply and demand of oxygen available to muscle cells is affected by duration and intensity and by the individual's cardio respiratory fitness level. It is also affected by the type of activity, for instance, during isometric activity the contracted muscles restricts blood flow (leaving oxygen and blood borne fuels unable to be delivered to muscle cells adequately for oxidative phosphorylation). Three sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purine Nucleotide Cycle
The Purine Nucleotide Cycle is a metabolic pathway in protein metabolism requiring the amino acids aspartate and glutamate. The cycle is used to regulate the levels of adenine nucleotides, in which ammonia and fumarate are generated. AMP converts into IMP and the byproduct ammonia. IMP converts to S-AMP ( adenylosuccinate), which then converts to AMP and the byproduct fumarate. The fumarate goes on to produce ATP (energy) via oxidative phosphorylation as it enters the Krebs cycle and then the electron transport chain. Lowenstein first described this pathway and outlined its importance in processes including amino acid catabolism and regulation of flux through glycolysis and the Krebs cycle. AMP is produced after strenuous muscle contraction when the ATP reservoir is low (ADP > ATP) by the adenylate kinase (myokinase) reaction. AMP is also produced from adenine and adenosine directly; however, AMP can be produced through less direct metabolic pathways, such as de novo synth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-energy Phosphate
High-energy phosphate can mean one of two things: * The phosphate-phosphate (phosphoanhydride/phosphoric anhydride/macroergic/ phosphagen) bonds formed when compounds such as adenosine diphosphate (ADP) and adenosine triphosphate (ATP) are created. * The compounds that contain these bonds, which include the nucleoside diphosphates and nucleoside triphosphates, and the high-energy storage compounds of the muscle, the phosphagens. When people speak of a high-energy phosphate pool, they speak of the total concentration of these compounds with these high-energy bonds. __TOC__ Description High-energy phosphate bonds are usually pyrophosphate bonds, acid anhydride linkages formed by taking phosphoric acid derivatives and dehydrating them. As a consequence, the hydrolysis of these bonds is exergonic under physiological conditions, releasing Gibbs free energy. Except for PPi → 2 Pi, these reactions are, in general, not allowed to go uncontrolled in the human cell but are instead coup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philip Eggleton
Philip Eggleton FRSE (19 March 1903 – 7 October 1954) was a British biochemist, physiologist, lecturer, and (with his wife Grace Palmer Eggleton), co-discoverer of Phosphagens. Life Eggleton was born at Kingston-on-Thames on 19 March 1903. He attended the Tiffin School there before going to the University of London graduating BSc in 1922 and receiving his doctorate (DSc) in 1930. He then received a post at the University of Edinburgh rising to Reader in Biochemistry in the Physiology Department. He also acted as Scientific Advisor to BBC Scotland. In 1927, in experiments on frog muscles in Cambridge, he discovered the release (on passing an electrical current) of a previously unknown substance which he labelled phosphagen. It was shown that the substance played a major role in muscular contraction. He was elected a Fellow of the Royal Society of Edinburgh in 1931. His proposers were Sir Edward Albert Sharpey-Schafer, Alfred Joseph Clark, and Henry Dryerre. During the Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lombricine
Lombricine is a phosphagen that is unique to earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...s. Structurally, it is a phosphodiester of 2-guanidinoethanol and D-serine (not the usual L-serine), which is then further phosphorylated by lombricine kinase to phospholombricine. References {{Reflist Organophosphates Guanidines Alpha-Amino acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenylate Kinase
Adenylate kinase ( ECbr>2.7.4.3 (also known as ADK or myokinase) is a phosphotransferase enzyme that catalyzes the interconversion of the various adenosine phosphates (ATP, ADP, and AMP). By constantly monitoring phosphate nucleotide levels inside the cell, ADK plays an important role in cellular energy homeostasis. Substrate and products The reaction catalyzed is: ATP + AMP ⇔ 2 ADP The equilibrium constant varies with condition, but it is close to 1. Thus, ΔGo for this reaction is close to zero. In muscle from a variety of species of vertebrates and invertebrates, the concentration of ATP is typically 7-10 times that of ADP, and usually greater than 100 times that of AMP. The rate of oxidative phosphorylation is controlled by the availability of ADP. Thus, the mitochondrion attempts to keep ATP levels high due to the combined action of adenylate kinase and the controls on oxidative phosphorylation. Isozymes To date there have been nine human ADK protein isoforms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creatine Kinase Reaction
Creatine ( or ) is an organic compound with the nominal formula . It exists in various tautomers in solutions (among which are neutral form and various zwitterionic forms). Creatine is found in vertebrates, where it facilitates recycling of adenosine triphosphate (ATP), primarily in muscle and brain tissue. Recycling is achieved by converting adenosine diphosphate (ADP) back to ATP via donation of phosphate groups. Creatine also acts as a buffer. History Creatine was first identified in 1832 when Michel Eugène Chevreul isolated it from the basified water-extract of skeletal muscle. He later named the crystallized precipitate after the Greek word for meat, ('). In 1928, creatine was shown to exist in equilibrium with creatinine. Studies in the 1920s showed that consumption of large amounts of creatine did not result in its excretion. This result pointed to the ability of the body to store creatine, which in turn suggested its use as a dietary supplement. In 1912, Harvard Un ... [...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] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known forms of life, it is often referred to as the "molecular unit of currency" for intracellular energy transfer. When consumed in a Metabolism, metabolic process, ATP converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. It is also a Precursor (chemistry), precursor to DNA and RNA, and is used as a coenzyme. An average adult human processes around 50 kilograms (about 100 mole (unit), moles) daily. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of three parts: a sugar, an amine base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creatine Phosphate
Phosphocreatine, also known as creatine phosphate (CP) or PCr (Pcr), is a phosphorylated form of creatine that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle, myocardium and the brain to recycle adenosine triphosphate (ATP), the energy currency of the cell. Chemistry In the kidneys, the enzyme AGAT catalyzes the conversion of two amino acids — arginine and glycine — into guanidinoacetate (also called glycocyamine or GAA), which is then transported in the blood to the liver. A methyl group is added to GAA from the amino acid methionine by the enzyme GAMT, forming non-phosphorylated creatine. This is then released into the blood by the liver where it travels mainly to the muscle cells (95% of the body's creatine is in muscles), and to a lesser extent the brain, heart, and pancreas. Once inside the cells it is transformed into phosphocreatine by the enzyme complex creatine kinase. Phosphocreatine is able to donate its phosphate group to co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creatine
Creatine ( or ) is an organic compound with the nominal formula . It exists in various tautomers in solutions (among which are neutral form and various zwitterionic forms). Creatine is found in vertebrates, where it facilitates recycling of adenosine triphosphate (ATP), primarily in muscle and brain tissue. Recycling is achieved by converting adenosine diphosphate (ADP) back to ATP via donation of phosphate groups. Creatine also acts as a Buffer solution, buffer. History Creatine was first identified in 1832 when Michel Eugène Chevreul isolated it from the basified water-extract of skeletal muscle. He later named the crystallized precipitate after the Ancient Greek, Greek word for meat, ('). In 1928, creatine was shown to exist in Tautomer, equilibrium with creatinine. Studies in the 1920s showed that consumption of large amounts of creatine did not result in its excretion. This result pointed to the ability of the body to store creatine, which in turn suggested its use as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
