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Thyroid Peroxidase
Thyroid peroxidase, also called thyroperoxidase (TPO), thyroid specific peroxidase or iodide peroxidase, is an enzyme expressed mainly in the thyroid where it is secreted into colloid. Thyroid peroxidase oxidizes iodide ions to form iodine atoms for addition onto tyrosine residues on thyroglobulin for the production of thyroxine (T4) or triiodothyronine (T3), the thyroid hormones. In humans, thyroperoxidase is encoded by the ''TPO'' gene. Function Inorganic iodine enters the body primarily as iodide, I−. After entering the thyroid follicle (or thyroid follicular cell) via a Na+/I− symporter (NIS) on the basolateral side, iodide is shuttled across the apical membrane into the colloid via pendrin after which thyroid peroxidase oxidizes iodide to atomic iodine (I) or iodinium (I+). The chemical reactions catalyzed by thyroid peroxidase occur on the outer apical membrane surface and are mediated by hydrogen peroxide. The "organification of iodine", the incorporation of iodine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), 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, 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 include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methimazole
Thiamazole, also known as methimazole, is a medication used to treat hyperthyroidism. This includes Graves' disease, toxic multinodular goiter, and thyrotoxic crisis. It is taken by mouth. Full effects may take a few weeks to occur. Common side effects include itchiness, hair loss, nausea, muscle pain, swelling, and abdominal pain. Severe side effects may include low blood cell counts, liver failure, and vasculitis. Use is not recommended during the first trimester of pregnancy due to the risk of congenital anomalies, but it may be used in the second trimester or third trimester. It may be used during breastfeeding. Those who developed significant side effects may also have problems with propylthiouracil. Thiamazole is a cyclic thiourea derivative that works by decreasing the production of thyroid hormones. Thiamazole was approved for medical use in the United States in 1950. It is on the World Health Organization's List of Essential Medicines. It is available as a ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propylthiouracil
Propylthiouracil (PTU) is a medication used to treat hyperthyroidism. This includes hyperthyroidism due to Graves' disease and toxic multinodular goiter. In a thyrotoxic crisis it is generally more effective than methimazole. Otherwise it is typically only used when methimazole, surgery, and radioactive iodine is not possible. It is taken by mouth. Common side effects include itchiness, hair loss, parotid swelling, vomiting, muscle pains, numbness, and headache. Other severe side effects include liver problems and low blood cell counts. Use during pregnancy may harm the baby. Propylthiouracil is in the antithyroid family of medications. It works by decreasing the amount of thyroid hormone produced by the thyroid gland and blocking the conversion of thyroxine (T4) to triiodothyronine (T3). Propylthiouracil came into medical use in the 1940s. It is on the World Health Organization's List of Essential Medicines. Side effects Propylthiouracil is generally well tolerated, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioamide
A thioamide (rarely, thionamide, but also known as thiourylenes) is a functional group with the general structure , where are any groups (typically organyl groups or hydrogen). Analogous to amides, thioamides exhibit greater multiple bond character along the C-N bond, resulting in a larger rotational barrier. Synthesis Thioamides are typically prepared by treating amides with phosphorus sulfides such as phosphorus pentasulfide, a reaction first described in the 1870s. An alternative to P2S5 is its more soluble analogue Lawesson's reagent. The Willgerodt-Kindler reaction can give benzylthioamides via an analogous process. These transformations can be seen in the synthesis of tolrestat. : The reaction of nitriles with hydrogen sulfide also affords thioamides: : Imidoyl chlorides react with hydrogen sulfide to produce thioamides. : Reactions A well-known thioamide is thioacetamide, which is used as a source of the sulfide ion. Thioamides are precursors to heterocycles. Such ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-Iodotyrosine
3-Iodotyrosine is an intermediate in the synthesis of thyroid hormones which is derived from iodination of tyrosine at the meta-position of the benzene ring. One unit can combine with diiodotyrosine to form triiodothyronine, as occurs in the colloid of the thyroid follicle. Two units can combine to form 3,3'-diiodothyronine. 3-Iodotyrosine is a reversible inhibitor of the enzyme tyrosine hydroxylase. Relevance in dopamine studies 3-Iodotyrosine, a pathway inhibitor in the synthesis of the neurotransmitter dopamine, was used to determine the effects of decreased dopamine levels in social spacing of ''Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly" ...''. 3-4 day old flies that were fed 3-iodotyrosine for 24 hours were shown to have altered dopamine l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diiodothyronines
3,3'-Diiodothyronine, also known as 3,3'-T2, is a metabolite of thyroid hormone. It is formed from the breakdown of triiodothyronine Triiodothyronine, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate. Production of T3 and its prohormone thyroxi .... Levels can be affected in certain disease states. Reactions References {{DEFAULTSORT:Diiodothyronine, 3,3'- Iodinated tyrosine derivatives Human hormones Hormones of the hypothalamus-pituitary-thyroid axis Hormones of the thyroid gland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Triiodothyronine
Reverse triiodothyronine, also known as rT3, is an isomer of triiodothyronine (T3). Reverse T3 is the third-most common iodothyronine the thyroid gland releases into the bloodstream, at 0.9%; tetraiodothyronine (levothyroxine, T4) constitutes 90% and T3 is 9%. However, 95% of rT3 in human blood is made elsewhere in the body, as enzymes remove a particular iodine atom from T4. The production of hormone by the thyroid gland is controlled by the hypothalamus and pituitary gland The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the human brain, brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus contr .... The physiological activity of thyroid hormone is regulated by a system of enzymes that activate, inactivate or simply discard the prohormone T4 and in turn functionally modify T3 and rT3. These enzymes operate under complex direction of systems including ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoiodous Acid
Hypoiodous acid is an inorganic compound with the chemical formula . It forms when an aqueous solution of iodine is treated with mercuric or silver salts. It rapidly decomposes by disproportionation: : Hypoiodous acid is a weak acid with a p''K''a of about 11. The conjugate base is hypoiodite (). Salts of this anion can be prepared by treating iodine with alkali hydroxides. They rapidly disproportionate to form iodides and iodates, but an iodine–hydroxide mixture can be used an in situ preparation of hypoiodite for other reactions. Ammonium hypoiodites can be formed by oxidation of the analogous iodide salts. These and also sodium hypoiodite are useful as oxidizing agents for a various types of organic compounds and also for a reaction analogous to the haloform reaction. Hypoiodite is one of the active oxidizing agents generated by lactoperoxidase as part of the mammalian innate immune system. Other oxyacids Hypoiodous acid is part of a series of oxyacids in whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liothyronine2DCSD
Liothyronine is a manufactured form of the thyroid hormone triiodothyronine (T3). It is most commonly used to treat hypothyroidism and myxedema coma. It can be taken by mouth or by injection into a vein. Side effects may occur from excessive doses. This may include weight loss, fever, headache, anxiety, trouble sleeping, arrhythmias, and heart failure. Use in pregnancy and breastfeeding is generally safe. Liothyronine was approved for medical use in 1956. It is available as a generic medication. In 2022, it was the 204th most commonly prescribed medication in the United States, with more than 1million prescriptions. Medical uses Liothyronine may be used when there is an impaired conversion of T4 to T3 in peripheral tissues. The dose of liothyronine for hypothyroidism is a lower amount than levothyroxine due it being a higher concentrated synthetic medication. About 25 μg of liothyronine is equivalent to 100 μg of levothyroxine. In thyroid cancer or Graves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
