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Metabolic Intermediate
Metabolic intermediates are molecules that are the precursors or metabolites of biologically significant molecules. Although these intermediates are of relatively minor direct importance to cellular function, they can play important roles in the allosteric regulation of enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...s. Clinical significance Some can be useful in measuring rates of metabolic processes (for example, 3,4-dihydroxyphenylacetic acid or 3-aminoisobutyrate). Because they can represent unnatural points of entry into natural metabolic pathways, some (such as AICA ribonucleotide) are of interest to researchers in developing new therapies. See also * Metabolism Metabolism {{chem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosteric
In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site. The site to which the effector binds is termed the ''allosteric site'' or ''regulatory site''. Allosteric sites allow effectors to bind to the protein, often resulting in a conformational change and/or a change in protein dynamics. Effectors that enhance the protein's activity are referred to as ''allosteric activators'', whereas those that decrease the protein's activity are called ''allosteric inhibitors''. Allosteric regulations are a natural example of control loops, such as feedback from downstream products or feedforward from upstream substrates. Long-range allostery is especially important in cell signaling. Allosteric regulation is also particularly important in the cell's ability to adjust enzyme activity. The term ''allostery'' comes from the Ancient Greek ''allos'' (), "other", and ''stereos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3,4-dihydroxyphenylacetic Acid
3,4-Dihydroxyphenylacetic acid (DOPAC) is a metabolite of the neurotransmitter dopamine. Dopamine can be metabolized into one of three substances. One such substance is DOPAC. Another is 3-methoxytyramine (3-MT). Both of these substances are degraded to form homovanillic acid (HVA). Both degradations involve the enzymes monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT), albeit in reverse order: MAO catalyzes dopamine to DOPAC, and COMT catalyzes DOPAC to HVA; whereas COMT catalyzes dopamine to 3-MT and MAO catalyzes 3-MT to HVA. The third metabolic end-product of dopamine is norepinephrine (noradrenaline). DOPAC can be oxidized by hydrogen peroxide, leading to the formation of toxic metabolites which destroy dopamine storage vesicles in the substantia nigra. This may contribute to the failure of levodopa treatment of Parkinson's disease. A MAO-B inhibitor such as selegiline or rasagiline can prevent this from happening. It can also be found in the bark o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-aminoisobutyrate
3-Aminoisobutyric acid (also known as β-aminoisobutyric acid or BAIBA) is a product formed by the catabolism of thymine. During exercise, the increase of PGC-1α protein triggers the secretion of BAIBA from exercising muscles to blood (concentration 2 to 3 μM in human serum). When BAIBA reaches the white fat tissue, it activates the expression of thermogenic genes via PPARα receptors, resulting in a browning of white fat cells. One of the consequences of the BAIBA activity is the increase of the background metabolism of the BAIBA target cells. It is thought to play a number of roles in cell metabolism, how body burns fat and regulates insulin, triglycerides, and total cholesterol. BAIBA is found as a normal metabolite of skeletal muscle in 2014. The plasma concentrations are increased in human by exercise. The production is likely a result of enhanced mitochondrial activity as the increase is also observed in the muscle of PGC-1a overexpression mice. BAIBA is proposed as pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AICA Ribonucleotide
5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) is an intermediate in the generation of inosine monophosphate. AICAR is an analog of adenosine monophosphate (AMP) that is capable of stimulating AMP-dependent protein kinase (AMPK) activity. The drug has also been shown as a potential treatment for diabetes by increasing the metabolic activity of tissues by changing the physical composition of muscle. Mechanism of action The nucleoside form of AICAR, acadesine, is an analog of adenosine that enters cardiac cells to inhibit adenosine kinase and adenosine deaminase. It enhances the rate of nucleotide re-synthesis increasing adenosine generation from adenosine monophosphate only during conditions of myocardial ischemia. In cardiac myocytes, acadesine is phosphorylated to AICAR to activate AMPK without changing the levels of the nucleotides. AICAR is able to enter the de novo synthesis pathway for adenosine synthesis to inhibit adenosine deaminase causing an increase in ATP level ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary (or intermediate) metabolism. Metabolic reactions may be categorized as '' catabolic'' – the ''breaking down'' of compounds (for example, of glucose to pyruvate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
