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ATPase Assay
The ATPase assay is a membrane assay that indirectly measures the activity of efflux transporters. ATP Binding Cassette or efflux transporters mediate the transport of substrates across cell membranes against a concentration gradient. ATP cleavage is tightly linked to substrate translocation, as the energy for the substrate translocation is derived from ATP hydrolysis ATP hydrolysis is the catabolic reaction process by which chemical energy that has been stored in the high-energy phosphoanhydride bonds in adenosine triphosphate (ATP) is released after splitting these bonds, for example in muscles, by prod .... ATP hydrolysis yields inorganic phosphate (Pi), which can be measured by a simple colorimetric reaction. The amount of Pi liberated is directly proportional to the activity of the transporter. Use of ATPase Assay The ATPase assay is designed to indicate the nature of the interaction between the compound and the transporter. The ATPase assays are used in two differe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assay
An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity. The measured entity is often called the analyte, the measurand, or the target of the assay. The analyte can be a drug, biochemical substance, chemical element or compound, or cell in an organism or organic sample. An assay usually aims to measure an analyte's intensive property and express it in the relevant measurement unit (e.g. molarity, density, functional activity in enzyme international units, degree of effect in comparison to a standard, etc.). If the assay involves exogenous reactants (the reagents), then their quantities are kept fixed (or in excess) so that the quantity and quality of the target are the only limiting factors. The difference in the assay outcome is used to deduce the unknown quality or quantity o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATP Binding Cassette Transporters
The ATP-binding cassette transporters (ABC transporters) are a transport system superfamily that is one of the largest and possibly one of the oldest gene families. It is represented in all extant phyla, from prokaryotes to humans. ABC transporters belong to translocases. ABC transporters often consist of multiple subunits, one or two of which are transmembrane proteins and one or two of which are membrane-associated AAA ATPases. The ATPase subunits utilize the energy of adenosine triphosphate (ATP) binding and hydrolysis to provide the energy needed for the translocation of substrates across membranes, either for uptake or for export of the substrate. Most of the uptake systems also have an extracytoplasmic receptor, a solute binding protein. Some homologous ATPases function in non-transport-related processes such as translation of RNA and DNA repair. ABC transporters are considered to be an ABC superfamily based on the similarities of the sequence and organization of their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer. When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. The human body recycles its own body weight equivalent in ATP each day. It is also a precursor to DNA and RNA, and is used as a coenzyme. 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 an adenine attached by the 9-nitrogen atom to the 1′ carbon atom of a sugar (ribose), which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (chemistry)
In chemistry, the term substrate is highly context-dependent. Broadly speaking, it can refer either to a chemical species being observed in a chemical reaction, or to a surface on which other chemical reactions or microscopy are performed. In the former sense, a reagent is added to the ''substrate'' to generate a product through a chemical reaction. The term is used in a similar sense in synthetic and organic chemistry, where the substrate is the chemical of interest that is being modified. In biochemistry, an enzyme substrate is the material upon which an enzyme acts. When referring to Le Chatelier's principle, the substrate is the reagent whose concentration is changed. ;Spontaneous reaction : :*Where S is substrate and P is product. ;Catalysed reaction : :*Where S is substrate, P is product and C is catalyst. In the latter sense, it may refer to a surface on which other chemical reactions are performed or play a supporting role in a variety of spectroscopic and microsco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration Gradient
Molecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration. Once the concentrations are equal the molecules continue to move, but since there is no concentration gradient the process of molecular diffusion has ceased and is instead governed by the process of self-diffusion, originating from the random motion of the molecules. The result of diffusion is a gradual mixing of material such that the distribution of molecules is uniform. Since the molecules are still in motion, but an equilibrium has been established, the result of molecular diffusion is called a "dynamic equilibrium". In a phase with uniform temperature, absent external net forces acting on the particles, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATP Hydrolysis
ATP hydrolysis is the catabolic reaction process by which chemical energy that has been stored in the high-energy phosphoanhydride bonds in adenosine triphosphate (ATP) is released after splitting these bonds, for example in muscles, by producing work in the form of mechanical energy. The product is adenosine diphosphate (ADP) and an inorganic phosphate (Pi). ADP can be further hydrolyzed to give energy, adenosine monophosphate (AMP), and another inorganic phosphate (Pi). ATP hydrolysis is the final link between the energy derived from food or sunlight and useful work such as muscle contraction, the establishment of electrochemical gradients across membranes, and biosynthetic processes necessary to maintain life. The description and typical textbook labels anhydridic bonds as "''high-energy bonds"''. P-O bonds are in fact fairly strong (~30 kJ/mol stronger than C-N bonds) Darwent, B. deB. (1970). "Bond Dissociation Energies in Simple Molecules", Nat. Stand. Ref. Data Ser., Na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
