Enzyme inhibitorAn enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity. Enzymes are proteins that speed up chemical reactions necessary for life, in which substrate molecules are converted into products. An enzyme facilitates a specific chemical reaction by binding the substrate to its active site, a specialized area on the enzyme that accelerates the most difficult step of the reaction.
Active siteIn biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate, the binding site, and residues that catalyse a reaction of that substrate, the catalytic site. Although the active site occupies only ~10–20% of the volume of an enzyme, it is the most important part as it directly catalyzes the chemical reaction.
Enzyme kineticsEnzyme kinetics is the study of the rates of enzyme-catalysed chemical reactions. In enzyme kinetics, the reaction rate is measured and the effects of varying the conditions of the reaction are investigated. Studying an enzyme's kinetics in this way can reveal the catalytic mechanism of this enzyme, its role in metabolism, how its activity is controlled, and how a drug or a modifier (inhibitor or activator) might affect the rate. An enzyme (E) is typically a protein molecule that promotes a reaction of another molecule, its substrate (S).
EnzymeEnzymes (ˈɛnzaɪmz) 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.
Suicide inhibitionIn biochemistry, suicide inhibition, also known as suicide inactivation or mechanism-based inhibition, is an irreversible form of enzyme inhibition that occurs when an enzyme binds a substrate analog and forms an irreversible complex with it through a covalent bond during the normal catalysis reaction. The inhibitor binds to the active site where it is modified by the enzyme to produce a reactive group that reacts irreversibly to form a stable inhibitor-enzyme complex.
Site-directed mutagenesisSite-directed mutagenesis is a molecular biology method that is used to make specific and intentional mutating changes to the DNA sequence of a gene and any gene products. Also called site-specific mutagenesis or oligonucleotide-directed mutagenesis, it is used for investigating the structure and biological activity of DNA, RNA, and protein molecules, and for protein engineering. Site-directed mutagenesis is one of the most important laboratory techniques for creating DNA libraries by introducing mutations into DNA sequences.
Non-competitive inhibitionNon-competitive inhibition is a type of enzyme inhibition where the inhibitor reduces the activity of the enzyme and binds equally well to the enzyme whether or not it has already bound the substrate. This is unlike competitive inhibition, where binding affinity for the substrate in the enzyme is decreased in the presence of an inhibitor. The inhibitor may bind to the enzyme whether or not the substrate has already been bound, but if it has a higher affinity for binding the enzyme in one state or the other, it is called a mixed inhibitor.
Monoamine oxidaseMonoamine oxidases (MAO) () are a family of enzymes that catalyze the oxidation of monoamines, employing oxygen to clip off their amine group. They are found bound to the outer membrane of mitochondria in most cell types of the body. The first such enzyme was discovered in 1928 by Mary Bernheim in the liver and was named tyramine oxidase. The MAOs belong to the protein family of flavin-containing amine oxidoreductases. MAOs are important in the breakdown of monoamines ingested in food, and also serve to inactivate monoamine neurotransmitters.
Directed evolutionDirected evolution (DE) is a method used in protein engineering that mimics the process of natural selection to steer proteins or nucleic acids toward a user-defined goal. It consists of subjecting a gene to iterative rounds of mutagenesis (creating a library of variants), selection (expressing those variants and isolating members with the desired function) and amplification (generating a template for the next round). It can be performed in vivo (in living organisms), or in vitro (in cells or free in solution).
Monoamine oxidase inhibitorMonoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as effective antidepressants, especially for treatment-resistant depression and atypical depression. They are also used to treat panic disorder, social anxiety disorder, Parkinson's disease, and several other disorders. Reversible inhibitors of monoamine oxidase A (RIMAs) are a subclass of MAOIs that selectively and reversibly inhibit the MAO-A enzyme.
Binding siteIn biochemistry and molecular biology, a binding site is a region on a macromolecule such as a protein that binds to another molecule with specificity. The binding partner of the macromolecule is often referred to as a ligand. Ligands may include other proteins (resulting in a protein-protein interaction), enzyme substrates, second messengers, hormones, or allosteric modulators. The binding event is often, but not always, accompanied by a conformational change that alters the protein's function.
RasagilineRasagiline (Azilect, Azipron) is an irreversible inhibitor of monoamine oxidase-B used as a monotherapy to treat symptoms in early Parkinson's disease or as an adjunct therapy in more advanced cases. The racemic form of the drug was invented by Aspro Nicholas in the early 1970s. Moussa B.H. Youdim identified it as a potential drug for Parkinson's disease, and working with collaborators at Technion – Israel Institute of Technology in Israel and the drug company, Teva Pharmaceuticals, identified the R-isomer as the active form of the drug.
SequenceIn mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called elements, or terms). The number of elements (possibly infinite) is called the length of the sequence. Unlike a set, the same elements can appear multiple times at different positions in a sequence, and unlike a set, the order does matter. Formally, a sequence can be defined as a function from natural numbers (the positions of elements in the sequence) to the elements at each position.
Catechol-O-methyltransferaseCatechol-O-methyltransferase (COMT; ) is one of several enzymes that degrade catecholamines (neurotransmitters such as dopamine, epinephrine, and norepinephrine), catecholestrogens, and various drugs and substances having a catechol structure. In humans, catechol-O-methyltransferase protein is encoded by the COMT gene. Two isoforms of COMT are produced: the soluble short form (S-COMT) and the membrane bound long form (MB-COMT).
Sequence spaceIn functional analysis and related areas of mathematics, a sequence space is a vector space whose elements are infinite sequences of real or complex numbers. Equivalently, it is a function space whose elements are functions from the natural numbers to the field K of real or complex numbers. The set of all such functions is naturally identified with the set of all possible infinite sequences with elements in K, and can be turned into a vector space under the operations of pointwise addition of functions and pointwise scalar multiplication.
Limit of a sequenceAs the positive integer becomes larger and larger, the value becomes arbitrarily close to . We say that "the limit of the sequence equals ." In mathematics, the limit of a sequence is the value that the terms of a sequence "tend to", and is often denoted using the symbol (e.g., ). If such a limit exists, the sequence is called convergent. A sequence that does not converge is said to be divergent. The limit of a sequence is said to be the fundamental notion on which the whole of mathematical analysis ultimately rests.
SelegilineSelegiline, also known as L-deprenyl and sold under the brand names Eldepryl and Emsam among others, is a medication which is used in the treatment of Parkinson's disease and major depressive disorder. It is provided in the form of a capsule or tablet taken by mouth for Parkinson's disease and as a patch applied to skin for depression. Selegiline acts as a monoamine oxidase inhibitor, and increases levels of monoamine neurotransmitters in the brain.
